use crate::{
    db::{self, NewUserParams, TestDb, UserId},
    executor::Executor,
    rpc::{Server, CLEANUP_TIMEOUT, RECONNECT_TIMEOUT},
    AppState,
};
use anyhow::anyhow;
use call::{room, ActiveCall, ParticipantLocation, Room};
use client::{
    self, test::FakeHttpClient, Client, Connection, Credentials, EstablishConnectionError, PeerId,
    User, UserStore, RECEIVE_TIMEOUT,
};
use collections::{BTreeMap, HashMap, HashSet};
use editor::{
    self, ConfirmCodeAction, ConfirmCompletion, ConfirmRename, Editor, ExcerptRange, MultiBuffer,
    Redo, Rename, ToOffset, ToggleCodeActions, Undo,
};
use fs::{FakeFs, Fs as _, HomeDir, LineEnding};
use futures::{channel::oneshot, StreamExt as _};
use gpui::{
    executor::Deterministic, geometry::vector::vec2f, test::EmptyView, ModelHandle, Task,
    TestAppContext, ViewHandle,
};
use language::{
    range_to_lsp, tree_sitter_rust, Anchor, Diagnostic, DiagnosticEntry, FakeLspAdapter, Language,
    LanguageConfig, LanguageRegistry, OffsetRangeExt, Point, PointUtf16, Rope,
};
use live_kit_client::MacOSDisplay;
use lsp::{self, FakeLanguageServer};
use parking_lot::Mutex;
use project::{search::SearchQuery, DiagnosticSummary, Project, ProjectPath, WorktreeId};
use rand::prelude::*;
use serde_json::json;
use settings::{Formatter, Settings};
use std::{
    cell::{Cell, RefCell},
    env, future, mem,
    ops::Deref,
    path::{Path, PathBuf},
    rc::Rc,
    sync::{
        atomic::{AtomicBool, AtomicUsize, Ordering::SeqCst},
        Arc,
    },
};
use theme::ThemeRegistry;
use unindent::Unindent as _;
use util::post_inc;
use workspace::{item::Item, shared_screen::SharedScreen, SplitDirection, ToggleFollow, Workspace};

#[ctor::ctor]
fn init_logger() {
    if std::env::var("RUST_LOG").is_ok() {
        env_logger::init();
    }
}

#[gpui::test(iterations = 10)]
async fn test_basic_calls(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_b2: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;

    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);
    let active_call_c = cx_c.read(ActiveCall::global);

    // Call user B from client A.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    let room_a = active_call_a.read_with(cx_a, |call, _| call.room().unwrap().clone());
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: Default::default(),
            pending: vec!["user_b".to_string()]
        }
    );

    // User B receives the call.
    let mut incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    let call_b = incoming_call_b.next().await.unwrap().unwrap();
    assert_eq!(call_b.calling_user.github_login, "user_a");

    // User B connects via another client and also receives a ring on the newly-connected client.
    let _client_b2 = server.create_client(cx_b2, "user_b").await;
    let active_call_b2 = cx_b2.read(ActiveCall::global);
    let mut incoming_call_b2 = active_call_b2.read_with(cx_b2, |call, _| call.incoming());
    deterministic.run_until_parked();
    let call_b2 = incoming_call_b2.next().await.unwrap().unwrap();
    assert_eq!(call_b2.calling_user.github_login, "user_a");

    // User B joins the room using the first client.
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let room_b = active_call_b.read_with(cx_b, |call, _| call.room().unwrap().clone());
    assert!(incoming_call_b.next().await.unwrap().is_none());

    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: Default::default()
        }
    );

    // Call user C from client B.
    let mut incoming_call_c = active_call_c.read_with(cx_c, |call, _| call.incoming());
    active_call_b
        .update(cx_b, |call, cx| {
            call.invite(client_c.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();

    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: vec!["user_c".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: vec!["user_c".to_string()]
        }
    );

    // User C receives the call, but declines it.
    let call_c = incoming_call_c.next().await.unwrap().unwrap();
    assert_eq!(call_c.calling_user.github_login, "user_b");
    active_call_c.update(cx_c, |call, _| call.decline_incoming().unwrap());
    assert!(incoming_call_c.next().await.unwrap().is_none());

    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: Default::default()
        }
    );

    // User A shares their screen
    let display = MacOSDisplay::new();
    let events_b = active_call_events(cx_b);
    active_call_a
        .update(cx_a, |call, cx| {
            call.room().unwrap().update(cx, |room, cx| {
                room.set_display_sources(vec![display.clone()]);
                room.share_screen(cx)
            })
        })
        .await
        .unwrap();

    deterministic.run_until_parked();

    assert_eq!(events_b.borrow().len(), 1);
    let event = events_b.borrow().first().unwrap().clone();
    if let call::room::Event::RemoteVideoTracksChanged { participant_id } = event {
        assert_eq!(participant_id, client_a.peer_id().unwrap());
        room_b.read_with(cx_b, |room, _| {
            assert_eq!(
                room.remote_participants()[&client_a.peer_id().unwrap()]
                    .tracks
                    .len(),
                1
            );
        });
    } else {
        panic!("unexpected event")
    }

    // User A leaves the room.
    active_call_a.update(cx_a, |call, cx| {
        call.hang_up(cx).unwrap();
        assert!(call.room().is_none());
    });
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );

    // User B gets disconnected from the LiveKit server, which causes them
    // to automatically leave the room.
    server
        .test_live_kit_server
        .disconnect_client(client_b.peer_id().unwrap().to_string())
        .await;
    active_call_b.update(cx_b, |call, _| assert!(call.room().is_none()));
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
}

#[gpui::test(iterations = 10)]
async fn test_room_uniqueness(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_a2: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_b2: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let _client_a2 = server.create_client(cx_a2, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let _client_b2 = server.create_client(cx_b2, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_a2 = cx_a2.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);
    let active_call_b2 = cx_b2.read(ActiveCall::global);
    let active_call_c = cx_c.read(ActiveCall::global);

    // Call user B from client A.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();

    // Ensure a new room can't be created given user A just created one.
    active_call_a2
        .update(cx_a2, |call, cx| {
            call.invite(client_c.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();
    active_call_a2.read_with(cx_a2, |call, _| assert!(call.room().is_none()));

    // User B receives the call from user A.
    let mut incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    let call_b1 = incoming_call_b.next().await.unwrap().unwrap();
    assert_eq!(call_b1.calling_user.github_login, "user_a");

    // Ensure calling users A and B from client C fails.
    active_call_c
        .update(cx_c, |call, cx| {
            call.invite(client_a.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();
    active_call_c
        .update(cx_c, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();

    // Ensure User B can't create a room while they still have an incoming call.
    active_call_b2
        .update(cx_b2, |call, cx| {
            call.invite(client_c.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();
    active_call_b2.read_with(cx_b2, |call, _| assert!(call.room().is_none()));

    // User B joins the room and calling them after they've joined still fails.
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    active_call_c
        .update(cx_c, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();

    // Ensure User B can't create a room while they belong to another room.
    active_call_b2
        .update(cx_b2, |call, cx| {
            call.invite(client_c.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap_err();
    active_call_b2.read_with(cx_b2, |call, _| assert!(call.room().is_none()));

    // Client C can successfully call client B after client B leaves the room.
    active_call_b
        .update(cx_b, |call, cx| call.hang_up(cx))
        .unwrap();
    deterministic.run_until_parked();
    active_call_c
        .update(cx_c, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    let call_b2 = incoming_call_b.next().await.unwrap().unwrap();
    assert_eq!(call_b2.calling_user.github_login, "user_c");
}

#[gpui::test(iterations = 10)]
async fn test_client_disconnecting_from_room(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    // Call user B from client A.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    let room_a = active_call_a.read_with(cx_a, |call, _| call.room().unwrap().clone());

    // User B receives the call and joins the room.
    let mut incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    incoming_call_b.next().await.unwrap().unwrap();
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let room_b = active_call_b.read_with(cx_b, |call, _| call.room().unwrap().clone());
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: Default::default()
        }
    );

    // User A automatically reconnects to the room upon disconnection.
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: Default::default()
        }
    );

    // When user A disconnects, both client A and B clear their room on the active call.
    server.forbid_connections();
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    active_call_a.read_with(cx_a, |call, _| assert!(call.room().is_none()));
    active_call_b.read_with(cx_b, |call, _| assert!(call.room().is_none()));
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );

    // Allow user A to reconnect to the server.
    server.allow_connections();
    deterministic.advance_clock(RECEIVE_TIMEOUT);

    // Call user B again from client A.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    let room_a = active_call_a.read_with(cx_a, |call, _| call.room().unwrap().clone());

    // User B receives the call and joins the room.
    let mut incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    incoming_call_b.next().await.unwrap().unwrap();
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let room_b = active_call_b.read_with(cx_b, |call, _| call.room().unwrap().clone());
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: Default::default()
        }
    );

    // User B gets disconnected from the LiveKit server, which causes it
    // to automatically leave the room.
    server
        .test_live_kit_server
        .disconnect_client(client_b.peer_id().unwrap().to_string())
        .await;
    deterministic.run_until_parked();
    active_call_a.update(cx_a, |call, _| assert!(call.room().is_none()));
    active_call_b.update(cx_b, |call, _| assert!(call.room().is_none()));
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: Default::default(),
            pending: Default::default()
        }
    );
}

#[gpui::test(iterations = 10)]
async fn test_server_restarts(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
    cx_d: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    let client_d = server.create_client(cx_d, "user_d").await;
    server
        .make_contacts(&mut [
            (&client_a, cx_a),
            (&client_b, cx_b),
            (&client_c, cx_c),
            (&client_d, cx_d),
        ])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);
    let active_call_c = cx_c.read(ActiveCall::global);
    let active_call_d = cx_d.read(ActiveCall::global);

    // User A calls users B, C, and D.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_c.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_d.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    let room_a = active_call_a.read_with(cx_a, |call, _| call.room().unwrap().clone());

    // User B receives the call and joins the room.
    let mut incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    assert!(incoming_call_b.next().await.unwrap().is_some());
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let room_b = active_call_b.read_with(cx_b, |call, _| call.room().unwrap().clone());

    // User C receives the call and joins the room.
    let mut incoming_call_c = active_call_c.read_with(cx_c, |call, _| call.incoming());
    assert!(incoming_call_c.next().await.unwrap().is_some());
    active_call_c
        .update(cx_c, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let room_c = active_call_c.read_with(cx_c, |call, _| call.room().unwrap().clone());

    // User D receives the call but doesn't join the room yet.
    let mut incoming_call_d = active_call_d.read_with(cx_d, |call, _| call.incoming());
    assert!(incoming_call_d.next().await.unwrap().is_some());

    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string(), "user_c".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string(), "user_c".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_c, cx_c),
        RoomParticipants {
            remote: vec!["user_a".to_string(), "user_b".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );

    // The server is torn down.
    server.teardown();

    // Users A and B reconnect to the call. User C has troubles reconnecting, so it leaves the room.
    client_c.override_establish_connection(|_, cx| cx.spawn(|_| future::pending()));
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string(), "user_c".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string(), "user_c".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_c, cx_c),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );

    // User D is notified again of the incoming call and accepts it.
    assert!(incoming_call_d.next().await.unwrap().is_some());
    active_call_d
        .update(cx_d, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    let room_d = active_call_d.read_with(cx_d, |call, _| call.room().unwrap().clone());
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec![
                "user_b".to_string(),
                "user_c".to_string(),
                "user_d".to_string(),
            ],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec![
                "user_a".to_string(),
                "user_c".to_string(),
                "user_d".to_string(),
            ],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_c, cx_c),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_d, cx_d),
        RoomParticipants {
            remote: vec![
                "user_a".to_string(),
                "user_b".to_string(),
                "user_c".to_string(),
            ],
            pending: vec![]
        }
    );

    // The server finishes restarting, cleaning up stale connections.
    server.start().await.unwrap();
    deterministic.advance_clock(CLEANUP_TIMEOUT);
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string(), "user_d".to_string()],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string(), "user_d".to_string()],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_c, cx_c),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_d, cx_d),
        RoomParticipants {
            remote: vec!["user_a".to_string(), "user_b".to_string()],
            pending: vec![]
        }
    );

    // User D hangs up.
    active_call_d
        .update(cx_d, |call, cx| call.hang_up(cx))
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_c, cx_c),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_d, cx_d),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );

    // User B calls user D again.
    active_call_b
        .update(cx_b, |call, cx| {
            call.invite(client_d.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();

    // User D receives the call but doesn't join the room yet.
    let mut incoming_call_d = active_call_d.read_with(cx_d, |call, _| call.incoming());
    assert!(incoming_call_d.next().await.unwrap().is_some());
    deterministic.run_until_parked();
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec!["user_b".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec!["user_a".to_string()],
            pending: vec!["user_d".to_string()]
        }
    );

    // The server is torn down.
    server.teardown();

    // Users A and B have troubles reconnecting, so they leave the room.
    client_a.override_establish_connection(|_, cx| cx.spawn(|_| future::pending()));
    client_b.override_establish_connection(|_, cx| cx.spawn(|_| future::pending()));
    client_c.override_establish_connection(|_, cx| cx.spawn(|_| future::pending()));
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    assert_eq!(
        room_participants(&room_a, cx_a),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );
    assert_eq!(
        room_participants(&room_b, cx_b),
        RoomParticipants {
            remote: vec![],
            pending: vec![]
        }
    );

    // User D is notified again of the incoming call but doesn't accept it.
    assert!(incoming_call_d.next().await.unwrap().is_some());

    // The server finishes restarting, cleaning up stale connections and canceling the
    // call to user D because the room has become empty.
    server.start().await.unwrap();
    deterministic.advance_clock(CLEANUP_TIMEOUT);
    assert!(incoming_call_d.next().await.unwrap().is_none());
}

#[gpui::test(iterations = 10)]
async fn test_calls_on_multiple_connections(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b1: &mut TestAppContext,
    cx_b2: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b1 = server.create_client(cx_b1, "user_b").await;
    let client_b2 = server.create_client(cx_b2, "user_b").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b1, cx_b1)])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b1 = cx_b1.read(ActiveCall::global);
    let active_call_b2 = cx_b2.read(ActiveCall::global);
    let mut incoming_call_b1 = active_call_b1.read_with(cx_b1, |call, _| call.incoming());
    let mut incoming_call_b2 = active_call_b2.read_with(cx_b2, |call, _| call.incoming());
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // Call user B from client A, ensuring both clients for user B ring.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User B declines the call on one of the two connections, causing both connections
    // to stop ringing.
    active_call_b2.update(cx_b2, |call, _| call.decline_incoming().unwrap());
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // Call user B again from client A.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User B accepts the call on one of the two connections, causing both connections
    // to stop ringing.
    active_call_b2
        .update(cx_b2, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // User B disconnects the client that is not on the call. Everything should be fine.
    client_b1.disconnect(&cx_b1.to_async()).unwrap();
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    client_b1
        .authenticate_and_connect(false, &cx_b1.to_async())
        .await
        .unwrap();

    // User B hangs up, and user A calls them again.
    active_call_b2.update(cx_b2, |call, cx| call.hang_up(cx).unwrap());
    deterministic.run_until_parked();
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User A cancels the call, causing both connections to stop ringing.
    active_call_a
        .update(cx_a, |call, cx| {
            call.cancel_invite(client_b1.user_id().unwrap(), cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // User A calls user B again.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User A hangs up, causing both connections to stop ringing.
    active_call_a.update(cx_a, |call, cx| call.hang_up(cx).unwrap());
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // User A calls user B again.
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User A disconnects, causing both connections to stop ringing.
    server.forbid_connections();
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    assert!(incoming_call_b1.next().await.unwrap().is_none());
    assert!(incoming_call_b2.next().await.unwrap().is_none());

    // User A reconnects automatically, then calls user B again.
    server.allow_connections();
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b1.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(incoming_call_b1.next().await.unwrap().is_some());
    assert!(incoming_call_b2.next().await.unwrap().is_some());

    // User B disconnects all clients, causing user A to no longer see a pending call for them.
    server.forbid_connections();
    server.disconnect_client(client_b1.peer_id().unwrap());
    server.disconnect_client(client_b2.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    active_call_a.read_with(cx_a, |call, _| assert!(call.room().is_none()));
}

#[gpui::test(iterations = 10)]
async fn test_share_project(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let (_, window_b) = cx_b.add_window(|_| EmptyView);
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);
    let active_call_c = cx_c.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                ".gitignore": "ignored-dir",
                "a.txt": "a-contents",
                "b.txt": "b-contents",
                "ignored-dir": {
                    "c.txt": "",
                    "d.txt": "",
                }
            }),
        )
        .await;

    // Invite client B to collaborate on a project
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), Some(project_a.clone()), cx)
        })
        .await
        .unwrap();

    // Join that project as client B
    let incoming_call_b = active_call_b.read_with(cx_b, |call, _| call.incoming());
    deterministic.run_until_parked();
    let call = incoming_call_b.borrow().clone().unwrap();
    assert_eq!(call.calling_user.github_login, "user_a");
    let initial_project = call.initial_project.unwrap();
    active_call_b
        .update(cx_b, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let client_b_peer_id = client_b.peer_id().unwrap();
    let project_b = client_b
        .build_remote_project(initial_project.id, cx_b)
        .await;
    let replica_id_b = project_b.read_with(cx_b, |project, _| project.replica_id());

    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        let client_b_collaborator = project.collaborators().get(&client_b_peer_id).unwrap();
        assert_eq!(client_b_collaborator.replica_id, replica_id_b);
    });
    project_b.read_with(cx_b, |project, cx| {
        let worktree = project.worktrees(cx).next().unwrap().read(cx);
        assert_eq!(
            worktree.paths().map(AsRef::as_ref).collect::<Vec<_>>(),
            [
                Path::new(".gitignore"),
                Path::new("a.txt"),
                Path::new("b.txt"),
                Path::new("ignored-dir"),
                Path::new("ignored-dir/c.txt"),
                Path::new("ignored-dir/d.txt"),
            ]
        );
    });

    // Open the same file as client B and client A.
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "b.txt"), cx))
        .await
        .unwrap();
    buffer_b.read_with(cx_b, |buf, _| assert_eq!(buf.text(), "b-contents"));
    project_a.read_with(cx_a, |project, cx| {
        assert!(project.has_open_buffer((worktree_id, "b.txt"), cx))
    });
    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "b.txt"), cx))
        .await
        .unwrap();

    let editor_b = cx_b.add_view(&window_b, |cx| Editor::for_buffer(buffer_b, None, cx));

    // Client A sees client B's selection
    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| {
        buffer
            .snapshot()
            .remote_selections_in_range(Anchor::MIN..Anchor::MAX)
            .count()
            == 1
    });

    // Edit the buffer as client B and see that edit as client A.
    editor_b.update(cx_b, |editor, cx| editor.handle_input("ok, ", cx));
    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.text(), "ok, b-contents")
    });

    // Client B can invite client C on a project shared by client A.
    active_call_b
        .update(cx_b, |call, cx| {
            call.invite(client_c.user_id().unwrap(), Some(project_b.clone()), cx)
        })
        .await
        .unwrap();

    let incoming_call_c = active_call_c.read_with(cx_c, |call, _| call.incoming());
    deterministic.run_until_parked();
    let call = incoming_call_c.borrow().clone().unwrap();
    assert_eq!(call.calling_user.github_login, "user_b");
    let initial_project = call.initial_project.unwrap();
    active_call_c
        .update(cx_c, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    let _project_c = client_c
        .build_remote_project(initial_project.id, cx_c)
        .await;

    // Client B closes the editor, and client A sees client B's selections removed.
    cx_b.update(move |_| drop(editor_b));
    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| {
        buffer
            .snapshot()
            .remote_selections_in_range(Anchor::MIN..Anchor::MAX)
            .count()
            == 0
    });
}

#[gpui::test(iterations = 10)]
async fn test_unshare_project(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "a.txt": "a-contents",
                "b.txt": "b-contents",
            }),
        )
        .await;

    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let worktree_a = project_a.read_with(cx_a, |project, cx| project.worktrees(cx).next().unwrap());
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    assert!(worktree_a.read_with(cx_a, |tree, _| tree.as_local().unwrap().is_shared()));

    project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // When client B leaves the room, the project becomes read-only.
    active_call_b.update(cx_b, |call, cx| call.hang_up(cx).unwrap());
    deterministic.run_until_parked();
    assert!(project_b.read_with(cx_b, |project, _| project.is_read_only()));

    // Client C opens the project.
    let project_c = client_c.build_remote_project(project_id, cx_c).await;

    // When client A unshares the project, client C's project becomes read-only.
    project_a
        .update(cx_a, |project, cx| project.unshare(cx))
        .unwrap();
    deterministic.run_until_parked();
    assert!(worktree_a.read_with(cx_a, |tree, _| !tree.as_local().unwrap().is_shared()));
    assert!(project_c.read_with(cx_c, |project, _| project.is_read_only()));

    // Client C can open the project again after client A re-shares.
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_c2 = client_c.build_remote_project(project_id, cx_c).await;
    assert!(worktree_a.read_with(cx_a, |tree, _| tree.as_local().unwrap().is_shared()));
    project_c2
        .update(cx_c, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // When client A (the host) leaves the room, the project gets unshared and guests are notified.
    active_call_a.update(cx_a, |call, cx| call.hang_up(cx).unwrap());
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| assert!(!project.is_shared()));
    project_c2.read_with(cx_c, |project, _| {
        assert!(project.is_read_only());
        assert!(project.collaborators().is_empty());
    });
}

#[gpui::test(iterations = 10)]
async fn test_host_disconnect(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    cx_b.update(editor::init);
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "a.txt": "a-contents",
                "b.txt": "b-contents",
            }),
        )
        .await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let worktree_a = project_a.read_with(cx_a, |project, cx| project.worktrees(cx).next().unwrap());
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    assert!(worktree_a.read_with(cx_a, |tree, _| tree.as_local().unwrap().is_shared()));

    let (_, workspace_b) = cx_b.add_window(|cx| {
        Workspace::new(
            Default::default(),
            0,
            project_b.clone(),
            |_, _| unimplemented!(),
            cx,
        )
    });
    let editor_b = workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "b.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();
    cx_b.read(|cx| {
        assert_eq!(
            cx.focused_view_id(workspace_b.window_id()),
            Some(editor_b.id())
        );
    });
    editor_b.update(cx_b, |editor, cx| editor.insert("X", cx));
    assert!(cx_b.is_window_edited(workspace_b.window_id()));

    // Drop client A's connection. Collaborators should disappear and the project should not be shown as shared.
    server.forbid_connections();
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    project_a.read_with(cx_a, |project, _| project.collaborators().is_empty());
    project_a.read_with(cx_a, |project, _| assert!(!project.is_shared()));
    project_b.read_with(cx_b, |project, _| project.is_read_only());
    assert!(worktree_a.read_with(cx_a, |tree, _| !tree.as_local().unwrap().is_shared()));

    // Ensure client B's edited state is reset and that the whole window is blurred.
    cx_b.read(|cx| {
        assert_eq!(cx.focused_view_id(workspace_b.window_id()), None);
    });
    assert!(!cx_b.is_window_edited(workspace_b.window_id()));

    // Ensure client B is not prompted to save edits when closing window after disconnecting.
    let can_close = workspace_b
        .update(cx_b, |workspace, cx| workspace.prepare_to_close(true, cx))
        .await
        .unwrap();
    assert!(can_close);

    // Allow client A to reconnect to the server.
    server.allow_connections();
    deterministic.advance_clock(RECEIVE_TIMEOUT);

    // Client B calls client A again after they reconnected.
    let active_call_b = cx_b.read(ActiveCall::global);
    active_call_b
        .update(cx_b, |call, cx| {
            call.invite(client_a.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    active_call_a
        .update(cx_a, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();

    active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    // Drop client A's connection again. We should still unshare it successfully.
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    project_a.read_with(cx_a, |project, _| assert!(!project.is_shared()));
}

#[gpui::test(iterations = 10)]
async fn test_active_call_events(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    client_a.fs.insert_tree("/a", json!({})).await;
    client_b.fs.insert_tree("/b", json!({})).await;

    let (project_a, _) = client_a.build_local_project("/a", cx_a).await;
    let (project_b, _) = client_b.build_local_project("/b", cx_b).await;

    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    let events_a = active_call_events(cx_a);
    let events_b = active_call_events(cx_b);

    let project_a_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(mem::take(&mut *events_a.borrow_mut()), vec![]);
    assert_eq!(
        mem::take(&mut *events_b.borrow_mut()),
        vec![room::Event::RemoteProjectShared {
            owner: Arc::new(User {
                id: client_a.user_id().unwrap(),
                github_login: "user_a".to_string(),
                avatar: None,
            }),
            project_id: project_a_id,
            worktree_root_names: vec!["a".to_string()],
        }]
    );

    let project_b_id = active_call_b
        .update(cx_b, |call, cx| call.share_project(project_b.clone(), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        mem::take(&mut *events_a.borrow_mut()),
        vec![room::Event::RemoteProjectShared {
            owner: Arc::new(User {
                id: client_b.user_id().unwrap(),
                github_login: "user_b".to_string(),
                avatar: None,
            }),
            project_id: project_b_id,
            worktree_root_names: vec!["b".to_string()]
        }]
    );
    assert_eq!(mem::take(&mut *events_b.borrow_mut()), vec![]);

    // Sharing a project twice is idempotent.
    let project_b_id_2 = active_call_b
        .update(cx_b, |call, cx| call.share_project(project_b.clone(), cx))
        .await
        .unwrap();
    assert_eq!(project_b_id_2, project_b_id);
    deterministic.run_until_parked();
    assert_eq!(mem::take(&mut *events_a.borrow_mut()), vec![]);
    assert_eq!(mem::take(&mut *events_b.borrow_mut()), vec![]);
}

fn active_call_events(cx: &mut TestAppContext) -> Rc<RefCell<Vec<room::Event>>> {
    let events = Rc::new(RefCell::new(Vec::new()));
    let active_call = cx.read(ActiveCall::global);
    cx.update({
        let events = events.clone();
        |cx| {
            cx.subscribe(&active_call, move |_, event, _| {
                events.borrow_mut().push(event.clone())
            })
            .detach()
        }
    });
    events
}

#[gpui::test(iterations = 10)]
async fn test_room_location(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    client_a.fs.insert_tree("/a", json!({})).await;
    client_b.fs.insert_tree("/b", json!({})).await;

    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    let a_notified = Rc::new(Cell::new(false));
    cx_a.update({
        let notified = a_notified.clone();
        |cx| {
            cx.observe(&active_call_a, move |_, _| notified.set(true))
                .detach()
        }
    });

    let b_notified = Rc::new(Cell::new(false));
    cx_b.update({
        let b_notified = b_notified.clone();
        |cx| {
            cx.observe(&active_call_b, move |_, _| b_notified.set(true))
                .detach()
        }
    });

    let (project_a, _) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| call.set_location(Some(&project_a), cx))
        .await
        .unwrap();
    let (project_b, _) = client_b.build_local_project("/b", cx_b).await;

    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let room_a = active_call_a.read_with(cx_a, |call, _| call.room().unwrap().clone());
    let room_b = active_call_b.read_with(cx_b, |call, _| call.room().unwrap().clone());
    deterministic.run_until_parked();
    assert!(a_notified.take());
    assert_eq!(
        participant_locations(&room_a, cx_a),
        vec![("user_b".to_string(), ParticipantLocation::External)]
    );
    assert!(b_notified.take());
    assert_eq!(
        participant_locations(&room_b, cx_b),
        vec![("user_a".to_string(), ParticipantLocation::UnsharedProject)]
    );

    let project_a_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(a_notified.take());
    assert_eq!(
        participant_locations(&room_a, cx_a),
        vec![("user_b".to_string(), ParticipantLocation::External)]
    );
    assert!(b_notified.take());
    assert_eq!(
        participant_locations(&room_b, cx_b),
        vec![(
            "user_a".to_string(),
            ParticipantLocation::SharedProject {
                project_id: project_a_id
            }
        )]
    );

    let project_b_id = active_call_b
        .update(cx_b, |call, cx| call.share_project(project_b.clone(), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(a_notified.take());
    assert_eq!(
        participant_locations(&room_a, cx_a),
        vec![("user_b".to_string(), ParticipantLocation::External)]
    );
    assert!(b_notified.take());
    assert_eq!(
        participant_locations(&room_b, cx_b),
        vec![(
            "user_a".to_string(),
            ParticipantLocation::SharedProject {
                project_id: project_a_id
            }
        )]
    );

    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(a_notified.take());
    assert_eq!(
        participant_locations(&room_a, cx_a),
        vec![(
            "user_b".to_string(),
            ParticipantLocation::SharedProject {
                project_id: project_b_id
            }
        )]
    );
    assert!(b_notified.take());
    assert_eq!(
        participant_locations(&room_b, cx_b),
        vec![(
            "user_a".to_string(),
            ParticipantLocation::SharedProject {
                project_id: project_a_id
            }
        )]
    );

    active_call_b
        .update(cx_b, |call, cx| call.set_location(None, cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert!(a_notified.take());
    assert_eq!(
        participant_locations(&room_a, cx_a),
        vec![("user_b".to_string(), ParticipantLocation::External)]
    );
    assert!(b_notified.take());
    assert_eq!(
        participant_locations(&room_b, cx_b),
        vec![(
            "user_a".to_string(),
            ParticipantLocation::SharedProject {
                project_id: project_a_id
            }
        )]
    );

    fn participant_locations(
        room: &ModelHandle<Room>,
        cx: &TestAppContext,
    ) -> Vec<(String, ParticipantLocation)> {
        room.read_with(cx, |room, _| {
            room.remote_participants()
                .values()
                .map(|participant| {
                    (
                        participant.user.github_login.to_string(),
                        participant.location,
                    )
                })
                .collect()
        })
    }
}

#[gpui::test(iterations = 10)]
async fn test_propagate_saves_and_fs_changes(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;

    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    let rust = Arc::new(Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    ));
    let javascript = Arc::new(Language::new(
        LanguageConfig {
            name: "JavaScript".into(),
            path_suffixes: vec!["js".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    ));
    for client in [&client_a, &client_b, &client_c] {
        client.language_registry.add(rust.clone());
        client.language_registry.add(javascript.clone());
    }

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "file1.rs": "",
                "file2": ""
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let worktree_a = project_a.read_with(cx_a, |p, cx| p.worktrees(cx).next().unwrap());
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    // Join that worktree as clients B and C.
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    let project_c = client_c.build_remote_project(project_id, cx_c).await;
    let worktree_b = project_b.read_with(cx_b, |p, cx| p.worktrees(cx).next().unwrap());
    let worktree_c = project_c.read_with(cx_c, |p, cx| p.worktrees(cx).next().unwrap());

    // Open and edit a buffer as both guests B and C.
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "file1.rs"), cx))
        .await
        .unwrap();
    let buffer_c = project_c
        .update(cx_c, |p, cx| p.open_buffer((worktree_id, "file1.rs"), cx))
        .await
        .unwrap();
    buffer_b.read_with(cx_b, |buffer, _| {
        assert_eq!(&*buffer.language().unwrap().name(), "Rust");
    });
    buffer_c.read_with(cx_c, |buffer, _| {
        assert_eq!(&*buffer.language().unwrap().name(), "Rust");
    });
    buffer_b.update(cx_b, |buf, cx| buf.edit([(0..0, "i-am-b, ")], None, cx));
    buffer_c.update(cx_c, |buf, cx| buf.edit([(0..0, "i-am-c, ")], None, cx));

    // Open and edit that buffer as the host.
    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "file1.rs"), cx))
        .await
        .unwrap();

    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buf, _| assert_eq!(buf.text(), "i-am-c, i-am-b, "));
    buffer_a.update(cx_a, |buf, cx| {
        buf.edit([(buf.len()..buf.len(), "i-am-a")], None, cx)
    });

    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buf, _| {
        assert_eq!(buf.text(), "i-am-c, i-am-b, i-am-a");
    });
    buffer_b.read_with(cx_b, |buf, _| {
        assert_eq!(buf.text(), "i-am-c, i-am-b, i-am-a");
    });
    buffer_c.read_with(cx_c, |buf, _| {
        assert_eq!(buf.text(), "i-am-c, i-am-b, i-am-a");
    });

    // Edit the buffer as the host and concurrently save as guest B.
    let save_b = buffer_b.update(cx_b, |buf, cx| buf.save(cx));
    buffer_a.update(cx_a, |buf, cx| buf.edit([(0..0, "hi-a, ")], None, cx));
    save_b.await.unwrap();
    assert_eq!(
        client_a.fs.load("/a/file1.rs".as_ref()).await.unwrap(),
        "hi-a, i-am-c, i-am-b, i-am-a"
    );

    deterministic.run_until_parked();
    buffer_a.read_with(cx_a, |buf, _| assert!(!buf.is_dirty()));
    buffer_b.read_with(cx_b, |buf, _| assert!(!buf.is_dirty()));
    buffer_c.read_with(cx_c, |buf, _| assert!(!buf.is_dirty()));

    // Make changes on host's file system, see those changes on guest worktrees.
    client_a
        .fs
        .rename(
            "/a/file1.rs".as_ref(),
            "/a/file1.js".as_ref(),
            Default::default(),
        )
        .await
        .unwrap();
    client_a
        .fs
        .rename("/a/file2".as_ref(), "/a/file3".as_ref(), Default::default())
        .await
        .unwrap();
    client_a.fs.insert_file("/a/file4", "4".into()).await;
    deterministic.run_until_parked();

    worktree_a.read_with(cx_a, |tree, _| {
        assert_eq!(
            tree.paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["file1.js", "file3", "file4"]
        )
    });
    worktree_b.read_with(cx_b, |tree, _| {
        assert_eq!(
            tree.paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["file1.js", "file3", "file4"]
        )
    });
    worktree_c.read_with(cx_c, |tree, _| {
        assert_eq!(
            tree.paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["file1.js", "file3", "file4"]
        )
    });

    // Ensure buffer files are updated as well.
    buffer_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.file().unwrap().path().to_str(), Some("file1.js"));
        assert_eq!(&*buffer.language().unwrap().name(), "JavaScript");
    });
    buffer_b.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.file().unwrap().path().to_str(), Some("file1.js"));
        assert_eq!(&*buffer.language().unwrap().name(), "JavaScript");
    });
    buffer_c.read_with(cx_c, |buffer, _| {
        assert_eq!(buffer.file().unwrap().path().to_str(), Some("file1.js"));
        assert_eq!(&*buffer.language().unwrap().name(), "JavaScript");
    });
}

#[gpui::test(iterations = 10)]
async fn test_git_diff_base_change(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
            ".git": {},
            "sub": {
                ".git": {},
                "b.txt": "
                    one
                    two
                    three
                ".unindent(),
            },
            "a.txt": "
                    one
                    two
                    three
                ".unindent(),
            }),
        )
        .await;

    let (project_local, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| {
            call.share_project(project_local.clone(), cx)
        })
        .await
        .unwrap();

    let project_remote = client_b.build_remote_project(project_id, cx_b).await;

    let diff_base = "
        one
        three
    "
    .unindent();

    let new_diff_base = "
        one
        two
    "
    .unindent();

    client_a
        .fs
        .as_fake()
        .set_index_for_repo(
            Path::new("/dir/.git"),
            &[(Path::new("a.txt"), diff_base.clone())],
        )
        .await;

    // Create the buffer
    let buffer_local_a = project_local
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // Wait for it to catch up to the new diff
    deterministic.run_until_parked();

    // Smoke test diffing
    buffer_local_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(1..2, "", "two\n")],
        );
    });

    // Create remote buffer
    let buffer_remote_a = project_remote
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // Wait remote buffer to catch up to the new diff
    deterministic.run_until_parked();

    // Smoke test diffing
    buffer_remote_a.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(1..2, "", "two\n")],
        );
    });

    client_a
        .fs
        .as_fake()
        .set_index_for_repo(
            Path::new("/dir/.git"),
            &[(Path::new("a.txt"), new_diff_base.clone())],
        )
        .await;

    // Wait for buffer_local_a to receive it
    deterministic.run_until_parked();

    // Smoke test new diffing
    buffer_local_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(new_diff_base.as_ref()));

        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(2..3, "", "three\n")],
        );
    });

    // Smoke test B
    buffer_remote_a.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(new_diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(2..3, "", "three\n")],
        );
    });

    //Nested git dir

    let diff_base = "
        one
        three
    "
    .unindent();

    let new_diff_base = "
        one
        two
    "
    .unindent();

    client_a
        .fs
        .as_fake()
        .set_index_for_repo(
            Path::new("/dir/sub/.git"),
            &[(Path::new("b.txt"), diff_base.clone())],
        )
        .await;

    // Create the buffer
    let buffer_local_b = project_local
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "sub/b.txt"), cx))
        .await
        .unwrap();

    // Wait for it to catch up to the new diff
    deterministic.run_until_parked();

    // Smoke test diffing
    buffer_local_b.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(1..2, "", "two\n")],
        );
    });

    // Create remote buffer
    let buffer_remote_b = project_remote
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "sub/b.txt"), cx))
        .await
        .unwrap();

    // Wait remote buffer to catch up to the new diff
    deterministic.run_until_parked();

    // Smoke test diffing
    buffer_remote_b.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(1..2, "", "two\n")],
        );
    });

    client_a
        .fs
        .as_fake()
        .set_index_for_repo(
            Path::new("/dir/sub/.git"),
            &[(Path::new("b.txt"), new_diff_base.clone())],
        )
        .await;

    // Wait for buffer_local_b to receive it
    deterministic.run_until_parked();

    // Smoke test new diffing
    buffer_local_b.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(new_diff_base.as_ref()));
        println!("{:?}", buffer.as_rope().to_string());
        println!("{:?}", buffer.diff_base());
        println!(
            "{:?}",
            buffer
                .snapshot()
                .git_diff_hunks_in_range(0..4, false)
                .collect::<Vec<_>>()
        );

        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(2..3, "", "three\n")],
        );
    });

    // Smoke test B
    buffer_remote_b.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.diff_base(), Some(new_diff_base.as_ref()));
        git::diff::assert_hunks(
            buffer.snapshot().git_diff_hunks_in_range(0..4, false),
            &buffer,
            &diff_base,
            &[(2..3, "", "three\n")],
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_fs_operations(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "a.txt": "a-contents",
                "b.txt": "b-contents",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let worktree_a = project_a.read_with(cx_a, |project, cx| project.worktrees(cx).next().unwrap());
    let worktree_b = project_b.read_with(cx_b, |project, cx| project.worktrees(cx).next().unwrap());

    let entry = project_b
        .update(cx_b, |project, cx| {
            project
                .create_entry((worktree_id, "c.txt"), false, cx)
                .unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "c.txt"]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "c.txt"]
        );
    });

    project_b
        .update(cx_b, |project, cx| {
            project.rename_entry(entry.id, Path::new("d.txt"), cx)
        })
        .unwrap()
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "d.txt"]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "d.txt"]
        );
    });

    let dir_entry = project_b
        .update(cx_b, |project, cx| {
            project
                .create_entry((worktree_id, "DIR"), true, cx)
                .unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["DIR", "a.txt", "b.txt", "d.txt"]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["DIR", "a.txt", "b.txt", "d.txt"]
        );
    });

    project_b
        .update(cx_b, |project, cx| {
            project
                .create_entry((worktree_id, "DIR/e.txt"), false, cx)
                .unwrap()
        })
        .await
        .unwrap();
    project_b
        .update(cx_b, |project, cx| {
            project
                .create_entry((worktree_id, "DIR/SUBDIR"), true, cx)
                .unwrap()
        })
        .await
        .unwrap();
    project_b
        .update(cx_b, |project, cx| {
            project
                .create_entry((worktree_id, "DIR/SUBDIR/f.txt"), false, cx)
                .unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            [
                "DIR",
                "DIR/SUBDIR",
                "DIR/SUBDIR/f.txt",
                "DIR/e.txt",
                "a.txt",
                "b.txt",
                "d.txt"
            ]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            [
                "DIR",
                "DIR/SUBDIR",
                "DIR/SUBDIR/f.txt",
                "DIR/e.txt",
                "a.txt",
                "b.txt",
                "d.txt"
            ]
        );
    });

    project_b
        .update(cx_b, |project, cx| {
            project
                .copy_entry(entry.id, Path::new("f.txt"), cx)
                .unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            [
                "DIR",
                "DIR/SUBDIR",
                "DIR/SUBDIR/f.txt",
                "DIR/e.txt",
                "a.txt",
                "b.txt",
                "d.txt",
                "f.txt"
            ]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            [
                "DIR",
                "DIR/SUBDIR",
                "DIR/SUBDIR/f.txt",
                "DIR/e.txt",
                "a.txt",
                "b.txt",
                "d.txt",
                "f.txt"
            ]
        );
    });

    project_b
        .update(cx_b, |project, cx| {
            project.delete_entry(dir_entry.id, cx).unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "d.txt", "f.txt"]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "d.txt", "f.txt"]
        );
    });

    project_b
        .update(cx_b, |project, cx| {
            project.delete_entry(entry.id, cx).unwrap()
        })
        .await
        .unwrap();
    worktree_a.read_with(cx_a, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "f.txt"]
        );
    });
    worktree_b.read_with(cx_b, |worktree, _| {
        assert_eq!(
            worktree
                .paths()
                .map(|p| p.to_string_lossy())
                .collect::<Vec<_>>(),
            ["a.txt", "b.txt", "f.txt"]
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_buffer_conflict_after_save(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "a.txt": "a-contents",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open a buffer as client B
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    buffer_b.update(cx_b, |buf, cx| buf.edit([(0..0, "world ")], None, cx));
    buffer_b.read_with(cx_b, |buf, _| {
        assert!(buf.is_dirty());
        assert!(!buf.has_conflict());
    });

    buffer_b.update(cx_b, |buf, cx| buf.save(cx)).await.unwrap();
    cx_a.foreground().forbid_parking();
    buffer_b.read_with(cx_b, |buffer_b, _| assert!(!buffer_b.is_dirty()));
    buffer_b.read_with(cx_b, |buf, _| {
        assert!(!buf.has_conflict());
    });

    buffer_b.update(cx_b, |buf, cx| buf.edit([(0..0, "hello ")], None, cx));
    buffer_b.read_with(cx_b, |buf, _| {
        assert!(buf.is_dirty());
        assert!(!buf.has_conflict());
    });
}

#[gpui::test(iterations = 10)]
async fn test_buffer_reloading(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "a.txt": "a\nb\nc",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open a buffer as client B
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();
    buffer_b.read_with(cx_b, |buf, _| {
        assert!(!buf.is_dirty());
        assert!(!buf.has_conflict());
        assert_eq!(buf.line_ending(), LineEnding::Unix);
    });

    let new_contents = Rope::from("d\ne\nf");
    client_a
        .fs
        .save("/dir/a.txt".as_ref(), &new_contents, LineEnding::Windows)
        .await
        .unwrap();
    cx_a.foreground().run_until_parked();
    buffer_b.read_with(cx_b, |buf, _| {
        assert_eq!(buf.text(), new_contents.to_string());
        assert!(!buf.is_dirty());
        assert!(!buf.has_conflict());
        assert_eq!(buf.line_ending(), LineEnding::Windows);
    });
}

#[gpui::test(iterations = 10)]
async fn test_editing_while_guest_opens_buffer(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree("/dir", json!({ "a.txt": "a-contents" }))
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open a buffer as client A
    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // Start opening the same buffer as client B
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx)));

    // Edit the buffer as client A while client B is still opening it.
    cx_b.background().simulate_random_delay().await;
    buffer_a.update(cx_a, |buf, cx| buf.edit([(0..0, "X")], None, cx));
    cx_b.background().simulate_random_delay().await;
    buffer_a.update(cx_a, |buf, cx| buf.edit([(1..1, "Y")], None, cx));

    let text = buffer_a.read_with(cx_a, |buf, _| buf.text());
    let buffer_b = buffer_b.await.unwrap();
    cx_a.foreground().run_until_parked();
    buffer_b.read_with(cx_b, |buf, _| assert_eq!(buf.text(), text));
}

#[gpui::test(iterations = 10)]
async fn test_leaving_worktree_while_opening_buffer(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree("/dir", json!({ "a.txt": "a-contents" }))
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // See that a guest has joined as client A.
    cx_a.foreground().run_until_parked();
    project_a.read_with(cx_a, |p, _| assert_eq!(p.collaborators().len(), 1));

    // Begin opening a buffer as client B, but leave the project before the open completes.
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx)));
    cx_b.update(|_| drop(project_b));
    drop(buffer_b);

    // See that the guest has left.
    cx_a.foreground().run_until_parked();
    project_a.read_with(cx_a, |p, _| assert!(p.collaborators().is_empty()));
}

#[gpui::test(iterations = 10)]
async fn test_canceling_buffer_opening(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "a.txt": "abc",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "a.txt"), cx))
        .await
        .unwrap();

    // Open a buffer as client B but cancel after a random amount of time.
    let buffer_b = project_b.update(cx_b, |p, cx| p.open_buffer_by_id(buffer_a.id() as u64, cx));
    deterministic.simulate_random_delay().await;
    drop(buffer_b);

    // Try opening the same buffer again as client B, and ensure we can
    // still do it despite the cancellation above.
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer_by_id(buffer_a.id() as u64, cx))
        .await
        .unwrap();
    buffer_b.read_with(cx_b, |buf, _| assert_eq!(buf.text(), "abc"));
}

#[gpui::test(iterations = 10)]
async fn test_leaving_project(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "a.txt": "a-contents",
                "b.txt": "b-contents",
            }),
        )
        .await;
    let (project_a, _) = client_a.build_local_project("/a", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b1 = client_b.build_remote_project(project_id, cx_b).await;
    let project_c = client_c.build_remote_project(project_id, cx_c).await;

    // Client A sees that a guest has joined.
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });
    project_b1.read_with(cx_b, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });
    project_c.read_with(cx_c, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });

    // Client B opens a buffer.
    let buffer_b1 = project_b1
        .update(cx_b, |project, cx| {
            let worktree_id = project.worktrees(cx).next().unwrap().read(cx).id();
            project.open_buffer((worktree_id, "a.txt"), cx)
        })
        .await
        .unwrap();
    buffer_b1.read_with(cx_b, |buffer, _| assert_eq!(buffer.text(), "a-contents"));

    // Drop client B's project and ensure client A and client C observe client B leaving.
    cx_b.update(|_| drop(project_b1));
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        assert_eq!(project.collaborators().len(), 1);
    });
    project_c.read_with(cx_c, |project, _| {
        assert_eq!(project.collaborators().len(), 1);
    });

    // Client B re-joins the project and can open buffers as before.
    let project_b2 = client_b.build_remote_project(project_id, cx_b).await;
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });
    project_b2.read_with(cx_b, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });
    project_c.read_with(cx_c, |project, _| {
        assert_eq!(project.collaborators().len(), 2);
    });

    let buffer_b2 = project_b2
        .update(cx_b, |project, cx| {
            let worktree_id = project.worktrees(cx).next().unwrap().read(cx).id();
            project.open_buffer((worktree_id, "a.txt"), cx)
        })
        .await
        .unwrap();
    buffer_b2.read_with(cx_b, |buffer, _| assert_eq!(buffer.text(), "a-contents"));

    // Drop client B's connection and ensure client A and client C observe client B leaving.
    client_b.disconnect(&cx_b.to_async()).unwrap();
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        assert_eq!(project.collaborators().len(), 1);
    });
    project_b2.read_with(cx_b, |project, _| {
        assert!(project.is_read_only());
    });
    project_c.read_with(cx_c, |project, _| {
        assert_eq!(project.collaborators().len(), 1);
    });

    // Client B can't join the project, unless they re-join the room.
    cx_b.spawn(|cx| {
        Project::remote(
            project_id,
            client_b.client.clone(),
            client_b.user_store.clone(),
            client_b.language_registry.clone(),
            FakeFs::new(cx.background()),
            cx,
        )
    })
    .await
    .unwrap_err();

    // Simulate connection loss for client C and ensure client A observes client C leaving the project.
    client_c.wait_for_current_user(cx_c).await;
    server.disconnect_client(client_c.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT);
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        assert_eq!(project.collaborators().len(), 0);
    });
    project_b2.read_with(cx_b, |project, _| {
        assert!(project.is_read_only());
    });
    project_c.read_with(cx_c, |project, _| {
        assert!(project.is_read_only());
    });
}

#[gpui::test(iterations = 10)]
async fn test_collaborating_with_diagnostics(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    // Share a project as client A
    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "a.rs": "let one = two",
                "other.rs": "",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;

    // Cause the language server to start.
    let _buffer = project_a
        .update(cx_a, |project, cx| {
            project.open_buffer(
                ProjectPath {
                    worktree_id,
                    path: Path::new("other.rs").into(),
                },
                cx,
            )
        })
        .await
        .unwrap();

    // Simulate a language server reporting errors for a file.
    let mut fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server
        .receive_notification::<lsp::notification::DidOpenTextDocument>()
        .await;
    fake_language_server.notify::<lsp::notification::PublishDiagnostics>(
        lsp::PublishDiagnosticsParams {
            uri: lsp::Url::from_file_path("/a/a.rs").unwrap(),
            version: None,
            diagnostics: vec![lsp::Diagnostic {
                severity: Some(lsp::DiagnosticSeverity::WARNING),
                range: lsp::Range::new(lsp::Position::new(0, 4), lsp::Position::new(0, 7)),
                message: "message 0".to_string(),
                ..Default::default()
            }],
        },
    );

    // Client A shares the project and, simultaneously, the language server
    // publishes a diagnostic. This is done to ensure that the server always
    // observes the latest diagnostics for a worktree.
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    fake_language_server.notify::<lsp::notification::PublishDiagnostics>(
        lsp::PublishDiagnosticsParams {
            uri: lsp::Url::from_file_path("/a/a.rs").unwrap(),
            version: None,
            diagnostics: vec![lsp::Diagnostic {
                severity: Some(lsp::DiagnosticSeverity::ERROR),
                range: lsp::Range::new(lsp::Position::new(0, 4), lsp::Position::new(0, 7)),
                message: "message 1".to_string(),
                ..Default::default()
            }],
        },
    );

    // Join the worktree as client B.
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Wait for server to see the diagnostics update.
    deterministic.run_until_parked();

    // Ensure client B observes the new diagnostics.
    project_b.read_with(cx_b, |project, cx| {
        assert_eq!(
            project.diagnostic_summaries(cx).collect::<Vec<_>>(),
            &[(
                ProjectPath {
                    worktree_id,
                    path: Arc::from(Path::new("a.rs")),
                },
                DiagnosticSummary {
                    error_count: 1,
                    warning_count: 0,
                    ..Default::default()
                },
            )]
        )
    });

    // Join project as client C and observe the diagnostics.
    let project_c = client_c.build_remote_project(project_id, cx_c).await;
    let project_c_diagnostic_summaries =
        Rc::new(RefCell::new(project_c.read_with(cx_c, |project, cx| {
            project.diagnostic_summaries(cx).collect::<Vec<_>>()
        })));
    project_c.update(cx_c, |_, cx| {
        let summaries = project_c_diagnostic_summaries.clone();
        cx.subscribe(&project_c, {
            move |p, _, event, cx| {
                if let project::Event::DiskBasedDiagnosticsFinished { .. } = event {
                    *summaries.borrow_mut() = p.diagnostic_summaries(cx).collect();
                }
            }
        })
        .detach();
    });

    deterministic.run_until_parked();
    assert_eq!(
        project_c_diagnostic_summaries.borrow().as_slice(),
        &[(
            ProjectPath {
                worktree_id,
                path: Arc::from(Path::new("a.rs")),
            },
            DiagnosticSummary {
                error_count: 1,
                warning_count: 0,
                ..Default::default()
            },
        )]
    );

    // Simulate a language server reporting more errors for a file.
    fake_language_server.notify::<lsp::notification::PublishDiagnostics>(
        lsp::PublishDiagnosticsParams {
            uri: lsp::Url::from_file_path("/a/a.rs").unwrap(),
            version: None,
            diagnostics: vec![
                lsp::Diagnostic {
                    severity: Some(lsp::DiagnosticSeverity::ERROR),
                    range: lsp::Range::new(lsp::Position::new(0, 4), lsp::Position::new(0, 7)),
                    message: "message 1".to_string(),
                    ..Default::default()
                },
                lsp::Diagnostic {
                    severity: Some(lsp::DiagnosticSeverity::WARNING),
                    range: lsp::Range::new(lsp::Position::new(0, 10), lsp::Position::new(0, 13)),
                    message: "message 2".to_string(),
                    ..Default::default()
                },
            ],
        },
    );

    // Clients B and C get the updated summaries
    deterministic.run_until_parked();
    project_b.read_with(cx_b, |project, cx| {
        assert_eq!(
            project.diagnostic_summaries(cx).collect::<Vec<_>>(),
            [(
                ProjectPath {
                    worktree_id,
                    path: Arc::from(Path::new("a.rs")),
                },
                DiagnosticSummary {
                    error_count: 1,
                    warning_count: 1,
                    ..Default::default()
                },
            )]
        );
    });
    project_c.read_with(cx_c, |project, cx| {
        assert_eq!(
            project.diagnostic_summaries(cx).collect::<Vec<_>>(),
            [(
                ProjectPath {
                    worktree_id,
                    path: Arc::from(Path::new("a.rs")),
                },
                DiagnosticSummary {
                    error_count: 1,
                    warning_count: 1,
                    ..Default::default()
                },
            )]
        );
    });

    // Open the file with the errors on client B. They should be present.
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx)))
        .await
        .unwrap();

    buffer_b.read_with(cx_b, |buffer, _| {
        assert_eq!(
            buffer
                .snapshot()
                .diagnostics_in_range::<_, Point>(0..buffer.len(), false)
                .collect::<Vec<_>>(),
            &[
                DiagnosticEntry {
                    range: Point::new(0, 4)..Point::new(0, 7),
                    diagnostic: Diagnostic {
                        group_id: 2,
                        message: "message 1".to_string(),
                        severity: lsp::DiagnosticSeverity::ERROR,
                        is_primary: true,
                        ..Default::default()
                    }
                },
                DiagnosticEntry {
                    range: Point::new(0, 10)..Point::new(0, 13),
                    diagnostic: Diagnostic {
                        group_id: 3,
                        severity: lsp::DiagnosticSeverity::WARNING,
                        message: "message 2".to_string(),
                        is_primary: true,
                        ..Default::default()
                    }
                }
            ]
        );
    });

    // Simulate a language server reporting no errors for a file.
    fake_language_server.notify::<lsp::notification::PublishDiagnostics>(
        lsp::PublishDiagnosticsParams {
            uri: lsp::Url::from_file_path("/a/a.rs").unwrap(),
            version: None,
            diagnostics: vec![],
        },
    );
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, cx| {
        assert_eq!(project.diagnostic_summaries(cx).collect::<Vec<_>>(), [])
    });
    project_b.read_with(cx_b, |project, cx| {
        assert_eq!(project.diagnostic_summaries(cx).collect::<Vec<_>>(), [])
    });
    project_c.read_with(cx_c, |project, cx| {
        assert_eq!(project.diagnostic_summaries(cx).collect::<Vec<_>>(), [])
    });
}

#[gpui::test(iterations = 10)]
async fn test_collaborating_with_completion(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language
        .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
            capabilities: lsp::ServerCapabilities {
                completion_provider: Some(lsp::CompletionOptions {
                    trigger_characters: Some(vec![".".to_string()]),
                    ..Default::default()
                }),
                ..Default::default()
            },
            ..Default::default()
        }))
        .await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "main.rs": "fn main() { a }",
                "other.rs": "",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open a file in an editor as the guest.
    let buffer_b = project_b
        .update(cx_b, |p, cx| p.open_buffer((worktree_id, "main.rs"), cx))
        .await
        .unwrap();
    let (_, window_b) = cx_b.add_window(|_| EmptyView);
    let editor_b = cx_b.add_view(&window_b, |cx| {
        Editor::for_buffer(buffer_b.clone(), Some(project_b.clone()), cx)
    });

    let fake_language_server = fake_language_servers.next().await.unwrap();
    cx_a.foreground().run_until_parked();
    buffer_b.read_with(cx_b, |buffer, _| {
        assert!(!buffer.completion_triggers().is_empty())
    });

    // Type a completion trigger character as the guest.
    editor_b.update(cx_b, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([13..13]));
        editor.handle_input(".", cx);
        cx.focus(&editor_b);
    });

    // Receive a completion request as the host's language server.
    // Return some completions from the host's language server.
    cx_a.foreground().start_waiting();
    fake_language_server
        .handle_request::<lsp::request::Completion, _, _>(|params, _| async move {
            assert_eq!(
                params.text_document_position.text_document.uri,
                lsp::Url::from_file_path("/a/main.rs").unwrap(),
            );
            assert_eq!(
                params.text_document_position.position,
                lsp::Position::new(0, 14),
            );

            Ok(Some(lsp::CompletionResponse::Array(vec![
                lsp::CompletionItem {
                    label: "first_method(…)".into(),
                    detail: Some("fn(&mut self, B) -> C".into()),
                    text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                        new_text: "first_method($1)".to_string(),
                        range: lsp::Range::new(
                            lsp::Position::new(0, 14),
                            lsp::Position::new(0, 14),
                        ),
                    })),
                    insert_text_format: Some(lsp::InsertTextFormat::SNIPPET),
                    ..Default::default()
                },
                lsp::CompletionItem {
                    label: "second_method(…)".into(),
                    detail: Some("fn(&mut self, C) -> D<E>".into()),
                    text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                        new_text: "second_method()".to_string(),
                        range: lsp::Range::new(
                            lsp::Position::new(0, 14),
                            lsp::Position::new(0, 14),
                        ),
                    })),
                    insert_text_format: Some(lsp::InsertTextFormat::SNIPPET),
                    ..Default::default()
                },
            ])))
        })
        .next()
        .await
        .unwrap();
    cx_a.foreground().finish_waiting();

    // Open the buffer on the host.
    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "main.rs"), cx))
        .await
        .unwrap();
    cx_a.foreground().run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.text(), "fn main() { a. }")
    });

    // Confirm a completion on the guest.
    editor_b.read_with(cx_b, |editor, _| assert!(editor.context_menu_visible()));
    editor_b.update(cx_b, |editor, cx| {
        editor.confirm_completion(&ConfirmCompletion { item_ix: Some(0) }, cx);
        assert_eq!(editor.text(cx), "fn main() { a.first_method() }");
    });

    // Return a resolved completion from the host's language server.
    // The resolved completion has an additional text edit.
    fake_language_server.handle_request::<lsp::request::ResolveCompletionItem, _, _>(
        |params, _| async move {
            assert_eq!(params.label, "first_method(…)");
            Ok(lsp::CompletionItem {
                label: "first_method(…)".into(),
                detail: Some("fn(&mut self, B) -> C".into()),
                text_edit: Some(lsp::CompletionTextEdit::Edit(lsp::TextEdit {
                    new_text: "first_method($1)".to_string(),
                    range: lsp::Range::new(lsp::Position::new(0, 14), lsp::Position::new(0, 14)),
                })),
                additional_text_edits: Some(vec![lsp::TextEdit {
                    new_text: "use d::SomeTrait;\n".to_string(),
                    range: lsp::Range::new(lsp::Position::new(0, 0), lsp::Position::new(0, 0)),
                }]),
                insert_text_format: Some(lsp::InsertTextFormat::SNIPPET),
                ..Default::default()
            })
        },
    );

    // The additional edit is applied.
    cx_a.foreground().run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| {
        assert_eq!(
            buffer.text(),
            "use d::SomeTrait;\nfn main() { a.first_method() }"
        );
    });
    buffer_b.read_with(cx_b, |buffer, _| {
        assert_eq!(
            buffer.text(),
            "use d::SomeTrait;\nfn main() { a.first_method() }"
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_reloading_buffer_manually(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree("/a", json!({ "a.rs": "let one = 1;" }))
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx))
        .await
        .unwrap();
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx)))
        .await
        .unwrap();
    buffer_b.update(cx_b, |buffer, cx| {
        buffer.edit([(4..7, "six")], None, cx);
        buffer.edit([(10..11, "6")], None, cx);
        assert_eq!(buffer.text(), "let six = 6;");
        assert!(buffer.is_dirty());
        assert!(!buffer.has_conflict());
    });
    cx_a.foreground().run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| assert_eq!(buffer.text(), "let six = 6;"));

    client_a
        .fs
        .save(
            "/a/a.rs".as_ref(),
            &Rope::from("let seven = 7;"),
            LineEnding::Unix,
        )
        .await
        .unwrap();
    cx_a.foreground().run_until_parked();
    buffer_a.read_with(cx_a, |buffer, _| assert!(buffer.has_conflict()));
    buffer_b.read_with(cx_b, |buffer, _| assert!(buffer.has_conflict()));

    project_b
        .update(cx_b, |project, cx| {
            project.reload_buffers(HashSet::from_iter([buffer_b.clone()]), true, cx)
        })
        .await
        .unwrap();
    buffer_a.read_with(cx_a, |buffer, _| {
        assert_eq!(buffer.text(), "let seven = 7;");
        assert!(!buffer.is_dirty());
        assert!(!buffer.has_conflict());
    });
    buffer_b.read_with(cx_b, |buffer, _| {
        assert_eq!(buffer.text(), "let seven = 7;");
        assert!(!buffer.is_dirty());
        assert!(!buffer.has_conflict());
    });

    buffer_a.update(cx_a, |buffer, cx| {
        // Undoing on the host is a no-op when the reload was initiated by the guest.
        buffer.undo(cx);
        assert_eq!(buffer.text(), "let seven = 7;");
        assert!(!buffer.is_dirty());
        assert!(!buffer.has_conflict());
    });
    buffer_b.update(cx_b, |buffer, cx| {
        // Undoing on the guest rolls back the buffer to before it was reloaded but the conflict gets cleared.
        buffer.undo(cx);
        assert_eq!(buffer.text(), "let six = 6;");
        assert!(buffer.is_dirty());
        assert!(!buffer.has_conflict());
    });
}

#[gpui::test(iterations = 10)]
async fn test_formatting_buffer(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    use project::FormatTrigger;

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    // Here we insert a fake tree with a directory that exists on disk. This is needed
    // because later we'll invoke a command, which requires passing a working directory
    // that points to a valid location on disk.
    let directory = env::current_dir().unwrap();
    client_a
        .fs
        .insert_tree(&directory, json!({ "a.rs": "let one = \"two\"" }))
        .await;
    let (project_a, worktree_id) = client_a.build_local_project(&directory, cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx)))
        .await
        .unwrap();

    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::Formatting, _, _>(|_, _| async move {
        Ok(Some(vec![
            lsp::TextEdit {
                range: lsp::Range::new(lsp::Position::new(0, 4), lsp::Position::new(0, 4)),
                new_text: "h".to_string(),
            },
            lsp::TextEdit {
                range: lsp::Range::new(lsp::Position::new(0, 7), lsp::Position::new(0, 7)),
                new_text: "y".to_string(),
            },
        ]))
    });

    project_b
        .update(cx_b, |project, cx| {
            project.format(
                HashSet::from_iter([buffer_b.clone()]),
                true,
                FormatTrigger::Save,
                cx,
            )
        })
        .await
        .unwrap();
    assert_eq!(
        buffer_b.read_with(cx_b, |buffer, _| buffer.text()),
        "let honey = \"two\""
    );

    // Ensure buffer can be formatted using an external command. Notice how the
    // host's configuration is honored as opposed to using the guest's settings.
    cx_a.update(|cx| {
        cx.update_global(|settings: &mut Settings, _| {
            settings.editor_defaults.formatter = Some(Formatter::External {
                command: "awk".to_string(),
                arguments: vec!["{sub(/two/,\"{buffer_path}\")}1".to_string()],
            });
        });
    });
    project_b
        .update(cx_b, |project, cx| {
            project.format(
                HashSet::from_iter([buffer_b.clone()]),
                true,
                FormatTrigger::Save,
                cx,
            )
        })
        .await
        .unwrap();
    assert_eq!(
        buffer_b.read_with(cx_b, |buffer, _| buffer.text()),
        format!("let honey = \"{}/a.rs\"\n", directory.to_str().unwrap())
    );
}

#[gpui::test(iterations = 10)]
async fn test_definition(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/root",
            json!({
                "dir-1": {
                    "a.rs": "const ONE: usize = b::TWO + b::THREE;",
                },
                "dir-2": {
                    "b.rs": "const TWO: c::T2 = 2;\nconst THREE: usize = 3;",
                    "c.rs": "type T2 = usize;",
                }
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/root/dir-1", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open the file on client B.
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx)))
        .await
        .unwrap();

    // Request the definition of a symbol as the guest.
    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::GotoDefinition, _, _>(|_, _| async move {
        Ok(Some(lsp::GotoDefinitionResponse::Scalar(
            lsp::Location::new(
                lsp::Url::from_file_path("/root/dir-2/b.rs").unwrap(),
                lsp::Range::new(lsp::Position::new(0, 6), lsp::Position::new(0, 9)),
            ),
        )))
    });

    let definitions_1 = project_b
        .update(cx_b, |p, cx| p.definition(&buffer_b, 23, cx))
        .await
        .unwrap();
    cx_b.read(|cx| {
        assert_eq!(definitions_1.len(), 1);
        assert_eq!(project_b.read(cx).worktrees(cx).count(), 2);
        let target_buffer = definitions_1[0].target.buffer.read(cx);
        assert_eq!(
            target_buffer.text(),
            "const TWO: c::T2 = 2;\nconst THREE: usize = 3;"
        );
        assert_eq!(
            definitions_1[0].target.range.to_point(target_buffer),
            Point::new(0, 6)..Point::new(0, 9)
        );
    });

    // Try getting more definitions for the same buffer, ensuring the buffer gets reused from
    // the previous call to `definition`.
    fake_language_server.handle_request::<lsp::request::GotoDefinition, _, _>(|_, _| async move {
        Ok(Some(lsp::GotoDefinitionResponse::Scalar(
            lsp::Location::new(
                lsp::Url::from_file_path("/root/dir-2/b.rs").unwrap(),
                lsp::Range::new(lsp::Position::new(1, 6), lsp::Position::new(1, 11)),
            ),
        )))
    });

    let definitions_2 = project_b
        .update(cx_b, |p, cx| p.definition(&buffer_b, 33, cx))
        .await
        .unwrap();
    cx_b.read(|cx| {
        assert_eq!(definitions_2.len(), 1);
        assert_eq!(project_b.read(cx).worktrees(cx).count(), 2);
        let target_buffer = definitions_2[0].target.buffer.read(cx);
        assert_eq!(
            target_buffer.text(),
            "const TWO: c::T2 = 2;\nconst THREE: usize = 3;"
        );
        assert_eq!(
            definitions_2[0].target.range.to_point(target_buffer),
            Point::new(1, 6)..Point::new(1, 11)
        );
    });
    assert_eq!(
        definitions_1[0].target.buffer,
        definitions_2[0].target.buffer
    );

    fake_language_server.handle_request::<lsp::request::GotoTypeDefinition, _, _>(
        |req, _| async move {
            assert_eq!(
                req.text_document_position_params.position,
                lsp::Position::new(0, 7)
            );
            Ok(Some(lsp::GotoDefinitionResponse::Scalar(
                lsp::Location::new(
                    lsp::Url::from_file_path("/root/dir-2/c.rs").unwrap(),
                    lsp::Range::new(lsp::Position::new(0, 5), lsp::Position::new(0, 7)),
                ),
            )))
        },
    );

    let type_definitions = project_b
        .update(cx_b, |p, cx| p.type_definition(&buffer_b, 7, cx))
        .await
        .unwrap();
    cx_b.read(|cx| {
        assert_eq!(type_definitions.len(), 1);
        let target_buffer = type_definitions[0].target.buffer.read(cx);
        assert_eq!(target_buffer.text(), "type T2 = usize;");
        assert_eq!(
            type_definitions[0].target.range.to_point(target_buffer),
            Point::new(0, 5)..Point::new(0, 7)
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_references(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/root",
            json!({
                "dir-1": {
                    "one.rs": "const ONE: usize = 1;",
                    "two.rs": "const TWO: usize = one::ONE + one::ONE;",
                },
                "dir-2": {
                    "three.rs": "const THREE: usize = two::TWO + one::ONE;",
                }
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/root/dir-1", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open the file on client B.
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "one.rs"), cx)))
        .await
        .unwrap();

    // Request references to a symbol as the guest.
    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::References, _, _>(|params, _| async move {
        assert_eq!(
            params.text_document_position.text_document.uri.as_str(),
            "file:///root/dir-1/one.rs"
        );
        Ok(Some(vec![
            lsp::Location {
                uri: lsp::Url::from_file_path("/root/dir-1/two.rs").unwrap(),
                range: lsp::Range::new(lsp::Position::new(0, 24), lsp::Position::new(0, 27)),
            },
            lsp::Location {
                uri: lsp::Url::from_file_path("/root/dir-1/two.rs").unwrap(),
                range: lsp::Range::new(lsp::Position::new(0, 35), lsp::Position::new(0, 38)),
            },
            lsp::Location {
                uri: lsp::Url::from_file_path("/root/dir-2/three.rs").unwrap(),
                range: lsp::Range::new(lsp::Position::new(0, 37), lsp::Position::new(0, 40)),
            },
        ]))
    });

    let references = project_b
        .update(cx_b, |p, cx| p.references(&buffer_b, 7, cx))
        .await
        .unwrap();
    cx_b.read(|cx| {
        assert_eq!(references.len(), 3);
        assert_eq!(project_b.read(cx).worktrees(cx).count(), 2);

        let two_buffer = references[0].buffer.read(cx);
        let three_buffer = references[2].buffer.read(cx);
        assert_eq!(
            two_buffer.file().unwrap().path().as_ref(),
            Path::new("two.rs")
        );
        assert_eq!(references[1].buffer, references[0].buffer);
        assert_eq!(
            three_buffer.file().unwrap().full_path(cx),
            Path::new("/root/dir-2/three.rs")
        );

        assert_eq!(references[0].range.to_offset(two_buffer), 24..27);
        assert_eq!(references[1].range.to_offset(two_buffer), 35..38);
        assert_eq!(references[2].range.to_offset(three_buffer), 37..40);
    });
}

#[gpui::test(iterations = 10)]
async fn test_project_search(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/root",
            json!({
                "dir-1": {
                    "a": "hello world",
                    "b": "goodnight moon",
                    "c": "a world of goo",
                    "d": "world champion of clown world",
                },
                "dir-2": {
                    "e": "disney world is fun",
                }
            }),
        )
        .await;
    let (project_a, _) = client_a.build_local_project("/root/dir-1", cx_a).await;
    let (worktree_2, _) = project_a
        .update(cx_a, |p, cx| {
            p.find_or_create_local_worktree("/root/dir-2", true, cx)
        })
        .await
        .unwrap();
    worktree_2
        .read_with(cx_a, |tree, _| tree.as_local().unwrap().scan_complete())
        .await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Perform a search as the guest.
    let results = project_b
        .update(cx_b, |project, cx| {
            project.search(SearchQuery::text("world", false, false), cx)
        })
        .await
        .unwrap();

    let mut ranges_by_path = results
        .into_iter()
        .map(|(buffer, ranges)| {
            buffer.read_with(cx_b, |buffer, cx| {
                let path = buffer.file().unwrap().full_path(cx);
                let offset_ranges = ranges
                    .into_iter()
                    .map(|range| range.to_offset(buffer))
                    .collect::<Vec<_>>();
                (path, offset_ranges)
            })
        })
        .collect::<Vec<_>>();
    ranges_by_path.sort_by_key(|(path, _)| path.clone());

    assert_eq!(
        ranges_by_path,
        &[
            (PathBuf::from("dir-1/a"), vec![6..11]),
            (PathBuf::from("dir-1/c"), vec![2..7]),
            (PathBuf::from("dir-1/d"), vec![0..5, 24..29]),
            (PathBuf::from("dir-2/e"), vec![7..12]),
        ]
    );
}

#[gpui::test(iterations = 10)]
async fn test_document_highlights(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/root-1",
            json!({
                "main.rs": "fn double(number: i32) -> i32 { number + number }",
            }),
        )
        .await;

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    let (project_a, worktree_id) = client_a.build_local_project("/root-1", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open the file on client B.
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "main.rs"), cx)))
        .await
        .unwrap();

    // Request document highlights as the guest.
    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::DocumentHighlightRequest, _, _>(
        |params, _| async move {
            assert_eq!(
                params
                    .text_document_position_params
                    .text_document
                    .uri
                    .as_str(),
                "file:///root-1/main.rs"
            );
            assert_eq!(
                params.text_document_position_params.position,
                lsp::Position::new(0, 34)
            );
            Ok(Some(vec![
                lsp::DocumentHighlight {
                    kind: Some(lsp::DocumentHighlightKind::WRITE),
                    range: lsp::Range::new(lsp::Position::new(0, 10), lsp::Position::new(0, 16)),
                },
                lsp::DocumentHighlight {
                    kind: Some(lsp::DocumentHighlightKind::READ),
                    range: lsp::Range::new(lsp::Position::new(0, 32), lsp::Position::new(0, 38)),
                },
                lsp::DocumentHighlight {
                    kind: Some(lsp::DocumentHighlightKind::READ),
                    range: lsp::Range::new(lsp::Position::new(0, 41), lsp::Position::new(0, 47)),
                },
            ]))
        },
    );

    let highlights = project_b
        .update(cx_b, |p, cx| p.document_highlights(&buffer_b, 34, cx))
        .await
        .unwrap();
    buffer_b.read_with(cx_b, |buffer, _| {
        let snapshot = buffer.snapshot();

        let highlights = highlights
            .into_iter()
            .map(|highlight| (highlight.kind, highlight.range.to_offset(&snapshot)))
            .collect::<Vec<_>>();
        assert_eq!(
            highlights,
            &[
                (lsp::DocumentHighlightKind::WRITE, 10..16),
                (lsp::DocumentHighlightKind::READ, 32..38),
                (lsp::DocumentHighlightKind::READ, 41..47)
            ]
        )
    });
}

#[gpui::test(iterations = 10)]
async fn test_lsp_hover(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/root-1",
            json!({
                "main.rs": "use std::collections::HashMap;",
            }),
        )
        .await;

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    let (project_a, worktree_id) = client_a.build_local_project("/root-1", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Open the file as the guest
    let buffer_b = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "main.rs"), cx)))
        .await
        .unwrap();

    // Request hover information as the guest.
    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::HoverRequest, _, _>(
        |params, _| async move {
            assert_eq!(
                params
                    .text_document_position_params
                    .text_document
                    .uri
                    .as_str(),
                "file:///root-1/main.rs"
            );
            assert_eq!(
                params.text_document_position_params.position,
                lsp::Position::new(0, 22)
            );
            Ok(Some(lsp::Hover {
                contents: lsp::HoverContents::Array(vec![
                    lsp::MarkedString::String("Test hover content.".to_string()),
                    lsp::MarkedString::LanguageString(lsp::LanguageString {
                        language: "Rust".to_string(),
                        value: "let foo = 42;".to_string(),
                    }),
                ]),
                range: Some(lsp::Range::new(
                    lsp::Position::new(0, 22),
                    lsp::Position::new(0, 29),
                )),
            }))
        },
    );

    let hover_info = project_b
        .update(cx_b, |p, cx| p.hover(&buffer_b, 22, cx))
        .await
        .unwrap()
        .unwrap();
    buffer_b.read_with(cx_b, |buffer, _| {
        let snapshot = buffer.snapshot();
        assert_eq!(hover_info.range.unwrap().to_offset(&snapshot), 22..29);
        assert_eq!(
            hover_info.contents,
            vec![
                project::HoverBlock {
                    text: "Test hover content.".to_string(),
                    language: None,
                },
                project::HoverBlock {
                    text: "let foo = 42;".to_string(),
                    language: Some("Rust".to_string()),
                }
            ]
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_project_symbols(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/code",
            json!({
                "crate-1": {
                    "one.rs": "const ONE: usize = 1;",
                },
                "crate-2": {
                    "two.rs": "const TWO: usize = 2; const THREE: usize = 3;",
                },
                "private": {
                    "passwords.txt": "the-password",
                }
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/code/crate-1", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    // Cause the language server to start.
    let _buffer = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "one.rs"), cx)))
        .await
        .unwrap();

    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::WorkspaceSymbol, _, _>(|_, _| async move {
        #[allow(deprecated)]
        Ok(Some(vec![lsp::SymbolInformation {
            name: "TWO".into(),
            location: lsp::Location {
                uri: lsp::Url::from_file_path("/code/crate-2/two.rs").unwrap(),
                range: lsp::Range::new(lsp::Position::new(0, 6), lsp::Position::new(0, 9)),
            },
            kind: lsp::SymbolKind::CONSTANT,
            tags: None,
            container_name: None,
            deprecated: None,
        }]))
    });

    // Request the definition of a symbol as the guest.
    let symbols = project_b
        .update(cx_b, |p, cx| p.symbols("two", cx))
        .await
        .unwrap();
    assert_eq!(symbols.len(), 1);
    assert_eq!(symbols[0].name, "TWO");

    // Open one of the returned symbols.
    let buffer_b_2 = project_b
        .update(cx_b, |project, cx| {
            project.open_buffer_for_symbol(&symbols[0], cx)
        })
        .await
        .unwrap();
    buffer_b_2.read_with(cx_b, |buffer, _| {
        assert_eq!(
            buffer.file().unwrap().path().as_ref(),
            Path::new("../crate-2/two.rs")
        );
    });

    // Attempt to craft a symbol and violate host's privacy by opening an arbitrary file.
    let mut fake_symbol = symbols[0].clone();
    fake_symbol.path.path = Path::new("/code/secrets").into();
    let error = project_b
        .update(cx_b, |project, cx| {
            project.open_buffer_for_symbol(&fake_symbol, cx)
        })
        .await
        .unwrap_err();
    assert!(error.to_string().contains("invalid symbol signature"));
}

#[gpui::test(iterations = 10)]
async fn test_open_buffer_while_getting_definition_pointing_to_it(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    mut rng: StdRng,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/root",
            json!({
                "a.rs": "const ONE: usize = b::TWO;",
                "b.rs": "const TWO: usize = 2",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/root", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let buffer_b1 = cx_b
        .background()
        .spawn(project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "a.rs"), cx)))
        .await
        .unwrap();

    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.handle_request::<lsp::request::GotoDefinition, _, _>(|_, _| async move {
        Ok(Some(lsp::GotoDefinitionResponse::Scalar(
            lsp::Location::new(
                lsp::Url::from_file_path("/root/b.rs").unwrap(),
                lsp::Range::new(lsp::Position::new(0, 6), lsp::Position::new(0, 9)),
            ),
        )))
    });

    let definitions;
    let buffer_b2;
    if rng.gen() {
        definitions = project_b.update(cx_b, |p, cx| p.definition(&buffer_b1, 23, cx));
        buffer_b2 = project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "b.rs"), cx));
    } else {
        buffer_b2 = project_b.update(cx_b, |p, cx| p.open_buffer((worktree_id, "b.rs"), cx));
        definitions = project_b.update(cx_b, |p, cx| p.definition(&buffer_b1, 23, cx));
    }

    let buffer_b2 = buffer_b2.await.unwrap();
    let definitions = definitions.await.unwrap();
    assert_eq!(definitions.len(), 1);
    assert_eq!(definitions[0].target.buffer, buffer_b2);
}

#[gpui::test(iterations = 10)]
async fn test_collaborating_with_code_actions(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_b.update(editor::init);
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language.set_fake_lsp_adapter(Default::default()).await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "main.rs": "mod other;\nfn main() { let foo = other::foo(); }",
                "other.rs": "pub fn foo() -> usize { 4 }",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    // Join the project as client B.
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    let (_window_b, workspace_b) = cx_b.add_window(|cx| {
        Workspace::new(
            Default::default(),
            0,
            project_b.clone(),
            |_, _| unimplemented!(),
            cx,
        )
    });
    let editor_b = workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "main.rs"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    let mut fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server
        .handle_request::<lsp::request::CodeActionRequest, _, _>(|params, _| async move {
            assert_eq!(
                params.text_document.uri,
                lsp::Url::from_file_path("/a/main.rs").unwrap(),
            );
            assert_eq!(params.range.start, lsp::Position::new(0, 0));
            assert_eq!(params.range.end, lsp::Position::new(0, 0));
            Ok(None)
        })
        .next()
        .await;

    // Move cursor to a location that contains code actions.
    editor_b.update(cx_b, |editor, cx| {
        editor.change_selections(None, cx, |s| {
            s.select_ranges([Point::new(1, 31)..Point::new(1, 31)])
        });
        cx.focus(&editor_b);
    });

    fake_language_server
        .handle_request::<lsp::request::CodeActionRequest, _, _>(|params, _| async move {
            assert_eq!(
                params.text_document.uri,
                lsp::Url::from_file_path("/a/main.rs").unwrap(),
            );
            assert_eq!(params.range.start, lsp::Position::new(1, 31));
            assert_eq!(params.range.end, lsp::Position::new(1, 31));

            Ok(Some(vec![lsp::CodeActionOrCommand::CodeAction(
                lsp::CodeAction {
                    title: "Inline into all callers".to_string(),
                    edit: Some(lsp::WorkspaceEdit {
                        changes: Some(
                            [
                                (
                                    lsp::Url::from_file_path("/a/main.rs").unwrap(),
                                    vec![lsp::TextEdit::new(
                                        lsp::Range::new(
                                            lsp::Position::new(1, 22),
                                            lsp::Position::new(1, 34),
                                        ),
                                        "4".to_string(),
                                    )],
                                ),
                                (
                                    lsp::Url::from_file_path("/a/other.rs").unwrap(),
                                    vec![lsp::TextEdit::new(
                                        lsp::Range::new(
                                            lsp::Position::new(0, 0),
                                            lsp::Position::new(0, 27),
                                        ),
                                        "".to_string(),
                                    )],
                                ),
                            ]
                            .into_iter()
                            .collect(),
                        ),
                        ..Default::default()
                    }),
                    data: Some(json!({
                        "codeActionParams": {
                            "range": {
                                "start": {"line": 1, "column": 31},
                                "end": {"line": 1, "column": 31},
                            }
                        }
                    })),
                    ..Default::default()
                },
            )]))
        })
        .next()
        .await;

    // Toggle code actions and wait for them to display.
    editor_b.update(cx_b, |editor, cx| {
        editor.toggle_code_actions(
            &ToggleCodeActions {
                deployed_from_indicator: false,
            },
            cx,
        );
    });
    cx_a.foreground().run_until_parked();
    editor_b.read_with(cx_b, |editor, _| assert!(editor.context_menu_visible()));

    fake_language_server.remove_request_handler::<lsp::request::CodeActionRequest>();

    // Confirming the code action will trigger a resolve request.
    let confirm_action = workspace_b
        .update(cx_b, |workspace, cx| {
            Editor::confirm_code_action(workspace, &ConfirmCodeAction { item_ix: Some(0) }, cx)
        })
        .unwrap();
    fake_language_server.handle_request::<lsp::request::CodeActionResolveRequest, _, _>(
        |_, _| async move {
            Ok(lsp::CodeAction {
                title: "Inline into all callers".to_string(),
                edit: Some(lsp::WorkspaceEdit {
                    changes: Some(
                        [
                            (
                                lsp::Url::from_file_path("/a/main.rs").unwrap(),
                                vec![lsp::TextEdit::new(
                                    lsp::Range::new(
                                        lsp::Position::new(1, 22),
                                        lsp::Position::new(1, 34),
                                    ),
                                    "4".to_string(),
                                )],
                            ),
                            (
                                lsp::Url::from_file_path("/a/other.rs").unwrap(),
                                vec![lsp::TextEdit::new(
                                    lsp::Range::new(
                                        lsp::Position::new(0, 0),
                                        lsp::Position::new(0, 27),
                                    ),
                                    "".to_string(),
                                )],
                            ),
                        ]
                        .into_iter()
                        .collect(),
                    ),
                    ..Default::default()
                }),
                ..Default::default()
            })
        },
    );

    // After the action is confirmed, an editor containing both modified files is opened.
    confirm_action.await.unwrap();
    let code_action_editor = workspace_b.read_with(cx_b, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<Editor>()
            .unwrap()
    });
    code_action_editor.update(cx_b, |editor, cx| {
        assert_eq!(editor.text(cx), "mod other;\nfn main() { let foo = 4; }\n");
        editor.undo(&Undo, cx);
        assert_eq!(
            editor.text(cx),
            "mod other;\nfn main() { let foo = other::foo(); }\npub fn foo() -> usize { 4 }"
        );
        editor.redo(&Redo, cx);
        assert_eq!(editor.text(cx), "mod other;\nfn main() { let foo = 4; }\n");
    });
}

#[gpui::test(iterations = 10)]
async fn test_collaborating_with_renames(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_b.update(editor::init);
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language
        .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
            capabilities: lsp::ServerCapabilities {
                rename_provider: Some(lsp::OneOf::Right(lsp::RenameOptions {
                    prepare_provider: Some(true),
                    work_done_progress_options: Default::default(),
                })),
                ..Default::default()
            },
            ..Default::default()
        }))
        .await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "one.rs": "const ONE: usize = 1;",
                "two.rs": "const TWO: usize = one::ONE + one::ONE;"
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;

    let (_window_b, workspace_b) = cx_b.add_window(|cx| {
        Workspace::new(
            Default::default(),
            0,
            project_b.clone(),
            |_, _| unimplemented!(),
            cx,
        )
    });
    let editor_b = workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "one.rs"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();
    let fake_language_server = fake_language_servers.next().await.unwrap();

    // Move cursor to a location that can be renamed.
    let prepare_rename = editor_b.update(cx_b, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([7..7]));
        editor.rename(&Rename, cx).unwrap()
    });

    fake_language_server
        .handle_request::<lsp::request::PrepareRenameRequest, _, _>(|params, _| async move {
            assert_eq!(params.text_document.uri.as_str(), "file:///dir/one.rs");
            assert_eq!(params.position, lsp::Position::new(0, 7));
            Ok(Some(lsp::PrepareRenameResponse::Range(lsp::Range::new(
                lsp::Position::new(0, 6),
                lsp::Position::new(0, 9),
            ))))
        })
        .next()
        .await
        .unwrap();
    prepare_rename.await.unwrap();
    editor_b.update(cx_b, |editor, cx| {
        let rename = editor.pending_rename().unwrap();
        let buffer = editor.buffer().read(cx).snapshot(cx);
        assert_eq!(
            rename.range.start.to_offset(&buffer)..rename.range.end.to_offset(&buffer),
            6..9
        );
        rename.editor.update(cx, |rename_editor, cx| {
            rename_editor.buffer().update(cx, |rename_buffer, cx| {
                rename_buffer.edit([(0..3, "THREE")], None, cx);
            });
        });
    });

    let confirm_rename = workspace_b.update(cx_b, |workspace, cx| {
        Editor::confirm_rename(workspace, &ConfirmRename, cx).unwrap()
    });
    fake_language_server
        .handle_request::<lsp::request::Rename, _, _>(|params, _| async move {
            assert_eq!(
                params.text_document_position.text_document.uri.as_str(),
                "file:///dir/one.rs"
            );
            assert_eq!(
                params.text_document_position.position,
                lsp::Position::new(0, 6)
            );
            assert_eq!(params.new_name, "THREE");
            Ok(Some(lsp::WorkspaceEdit {
                changes: Some(
                    [
                        (
                            lsp::Url::from_file_path("/dir/one.rs").unwrap(),
                            vec![lsp::TextEdit::new(
                                lsp::Range::new(lsp::Position::new(0, 6), lsp::Position::new(0, 9)),
                                "THREE".to_string(),
                            )],
                        ),
                        (
                            lsp::Url::from_file_path("/dir/two.rs").unwrap(),
                            vec![
                                lsp::TextEdit::new(
                                    lsp::Range::new(
                                        lsp::Position::new(0, 24),
                                        lsp::Position::new(0, 27),
                                    ),
                                    "THREE".to_string(),
                                ),
                                lsp::TextEdit::new(
                                    lsp::Range::new(
                                        lsp::Position::new(0, 35),
                                        lsp::Position::new(0, 38),
                                    ),
                                    "THREE".to_string(),
                                ),
                            ],
                        ),
                    ]
                    .into_iter()
                    .collect(),
                ),
                ..Default::default()
            }))
        })
        .next()
        .await
        .unwrap();
    confirm_rename.await.unwrap();

    let rename_editor = workspace_b.read_with(cx_b, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<Editor>()
            .unwrap()
    });
    rename_editor.update(cx_b, |editor, cx| {
        assert_eq!(
            editor.text(cx),
            "const THREE: usize = 1;\nconst TWO: usize = one::THREE + one::THREE;"
        );
        editor.undo(&Undo, cx);
        assert_eq!(
            editor.text(cx),
            "const ONE: usize = 1;\nconst TWO: usize = one::ONE + one::ONE;"
        );
        editor.redo(&Redo, cx);
        assert_eq!(
            editor.text(cx),
            "const THREE: usize = 1;\nconst TWO: usize = one::THREE + one::THREE;"
        );
    });

    // Ensure temporary rename edits cannot be undone/redone.
    editor_b.update(cx_b, |editor, cx| {
        editor.undo(&Undo, cx);
        assert_eq!(editor.text(cx), "const ONE: usize = 1;");
        editor.undo(&Undo, cx);
        assert_eq!(editor.text(cx), "const ONE: usize = 1;");
        editor.redo(&Redo, cx);
        assert_eq!(editor.text(cx), "const THREE: usize = 1;");
    })
}

#[gpui::test(iterations = 10)]
async fn test_language_server_statuses(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();

    cx_b.update(editor::init);
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    // Set up a fake language server.
    let mut language = Language::new(
        LanguageConfig {
            name: "Rust".into(),
            path_suffixes: vec!["rs".to_string()],
            ..Default::default()
        },
        Some(tree_sitter_rust::language()),
    );
    let mut fake_language_servers = language
        .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
            name: "the-language-server",
            ..Default::default()
        }))
        .await;
    client_a.language_registry.add(Arc::new(language));

    client_a
        .fs
        .insert_tree(
            "/dir",
            json!({
                "main.rs": "const ONE: usize = 1;",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/dir", cx_a).await;

    let _buffer_a = project_a
        .update(cx_a, |p, cx| p.open_buffer((worktree_id, "main.rs"), cx))
        .await
        .unwrap();

    let fake_language_server = fake_language_servers.next().await.unwrap();
    fake_language_server.start_progress("the-token").await;
    fake_language_server.notify::<lsp::notification::Progress>(lsp::ProgressParams {
        token: lsp::NumberOrString::String("the-token".to_string()),
        value: lsp::ProgressParamsValue::WorkDone(lsp::WorkDoneProgress::Report(
            lsp::WorkDoneProgressReport {
                message: Some("the-message".to_string()),
                ..Default::default()
            },
        )),
    });
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        let status = project.language_server_statuses().next().unwrap();
        assert_eq!(status.name, "the-language-server");
        assert_eq!(status.pending_work.len(), 1);
        assert_eq!(
            status.pending_work["the-token"].message.as_ref().unwrap(),
            "the-message"
        );
    });

    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    project_b.read_with(cx_b, |project, _| {
        let status = project.language_server_statuses().next().unwrap();
        assert_eq!(status.name, "the-language-server");
    });

    fake_language_server.notify::<lsp::notification::Progress>(lsp::ProgressParams {
        token: lsp::NumberOrString::String("the-token".to_string()),
        value: lsp::ProgressParamsValue::WorkDone(lsp::WorkDoneProgress::Report(
            lsp::WorkDoneProgressReport {
                message: Some("the-message-2".to_string()),
                ..Default::default()
            },
        )),
    });
    deterministic.run_until_parked();
    project_a.read_with(cx_a, |project, _| {
        let status = project.language_server_statuses().next().unwrap();
        assert_eq!(status.name, "the-language-server");
        assert_eq!(status.pending_work.len(), 1);
        assert_eq!(
            status.pending_work["the-token"].message.as_ref().unwrap(),
            "the-message-2"
        );
    });
    project_b.read_with(cx_b, |project, _| {
        let status = project.language_server_statuses().next().unwrap();
        assert_eq!(status.name, "the-language-server");
        assert_eq!(status.pending_work.len(), 1);
        assert_eq!(
            status.pending_work["the-token"].message.as_ref().unwrap(),
            "the-message-2"
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_contacts(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_c: &mut TestAppContext,
    cx_d: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    let client_d = server.create_client(cx_d, "user_d").await;
    server
        .make_contacts(&mut [(&client_a, cx_a), (&client_b, cx_b), (&client_c, cx_c)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);
    let active_call_c = cx_c.read(ActiveCall::global);
    let _active_call_d = cx_d.read(ActiveCall::global);

    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(contacts(&client_d, cx_d), []);

    server.disconnect_client(client_c.peer_id().unwrap());
    server.forbid_connections();
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "offline", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_c".to_string(), "offline", "free")
        ]
    );
    assert_eq!(contacts(&client_c, cx_c), []);
    assert_eq!(contacts(&client_d, cx_d), []);

    server.allow_connections();
    client_c
        .authenticate_and_connect(false, &cx_c.to_async())
        .await
        .unwrap();

    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(contacts(&client_d, cx_d), []);

    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "busy")
        ]
    );
    assert_eq!(contacts(&client_d, cx_d), []);

    // Client B and client D become contacts while client B is being called.
    server
        .make_contacts(&mut [(&client_b, cx_b), (&client_d, cx_d)])
        .await;
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free"),
            ("user_d".to_string(), "online", "free"),
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "busy")]
    );

    active_call_b.update(cx_b, |call, _| call.decline_incoming().unwrap());
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "free")]
    );

    active_call_c
        .update(cx_c, |call, cx| {
            call.invite(client_a.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "busy"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "free")]
    );

    active_call_a
        .update(cx_a, |call, cx| call.accept_incoming(cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "busy"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "free")]
    );

    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "busy"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "busy")]
    );

    active_call_a.update(cx_a, |call, cx| call.hang_up(cx).unwrap());
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_c".to_string(), "online", "free"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "free"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "free")]
    );

    active_call_a
        .update(cx_a, |call, cx| {
            call.invite(client_b.user_id().unwrap(), None, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        contacts(&client_a, cx_a),
        [
            ("user_b".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_c".to_string(), "online", "free"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "online", "busy"),
            ("user_b".to_string(), "online", "busy")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "busy")]
    );

    server.forbid_connections();
    server.disconnect_client(client_a.peer_id().unwrap());
    deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
    assert_eq!(contacts(&client_a, cx_a), []);
    assert_eq!(
        contacts(&client_b, cx_b),
        [
            ("user_a".to_string(), "offline", "free"),
            ("user_c".to_string(), "online", "free"),
            ("user_d".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_c, cx_c),
        [
            ("user_a".to_string(), "offline", "free"),
            ("user_b".to_string(), "online", "free")
        ]
    );
    assert_eq!(
        contacts(&client_d, cx_d),
        [("user_b".to_string(), "online", "free")]
    );

    fn contacts(
        client: &TestClient,
        cx: &TestAppContext,
    ) -> Vec<(String, &'static str, &'static str)> {
        client.user_store.read_with(cx, |store, _| {
            store
                .contacts()
                .iter()
                .map(|contact| {
                    (
                        contact.user.github_login.clone(),
                        if contact.online { "online" } else { "offline" },
                        if contact.busy { "busy" } else { "free" },
                    )
                })
                .collect()
        })
    }
}

#[gpui::test(iterations = 10)]
async fn test_contact_requests(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_a2: &mut TestAppContext,
    cx_b: &mut TestAppContext,
    cx_b2: &mut TestAppContext,
    cx_c: &mut TestAppContext,
    cx_c2: &mut TestAppContext,
) {
    deterministic.forbid_parking();

    // Connect to a server as 3 clients.
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_a2 = server.create_client(cx_a2, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    let client_b2 = server.create_client(cx_b2, "user_b").await;
    let client_c = server.create_client(cx_c, "user_c").await;
    let client_c2 = server.create_client(cx_c2, "user_c").await;

    assert_eq!(client_a.user_id().unwrap(), client_a2.user_id().unwrap());
    assert_eq!(client_b.user_id().unwrap(), client_b2.user_id().unwrap());
    assert_eq!(client_c.user_id().unwrap(), client_c2.user_id().unwrap());

    // User A and User C request that user B become their contact.
    client_a
        .user_store
        .update(cx_a, |store, cx| {
            store.request_contact(client_b.user_id().unwrap(), cx)
        })
        .await
        .unwrap();
    client_c
        .user_store
        .update(cx_c, |store, cx| {
            store.request_contact(client_b.user_id().unwrap(), cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();

    // All users see the pending request appear in all their clients.
    assert_eq!(
        client_a.summarize_contacts(cx_a).outgoing_requests,
        &["user_b"]
    );
    assert_eq!(
        client_a2.summarize_contacts(cx_a2).outgoing_requests,
        &["user_b"]
    );
    assert_eq!(
        client_b.summarize_contacts(cx_b).incoming_requests,
        &["user_a", "user_c"]
    );
    assert_eq!(
        client_b2.summarize_contacts(cx_b2).incoming_requests,
        &["user_a", "user_c"]
    );
    assert_eq!(
        client_c.summarize_contacts(cx_c).outgoing_requests,
        &["user_b"]
    );
    assert_eq!(
        client_c2.summarize_contacts(cx_c2).outgoing_requests,
        &["user_b"]
    );

    // Contact requests are present upon connecting (tested here via disconnect/reconnect)
    disconnect_and_reconnect(&client_a, cx_a).await;
    disconnect_and_reconnect(&client_b, cx_b).await;
    disconnect_and_reconnect(&client_c, cx_c).await;
    deterministic.run_until_parked();
    assert_eq!(
        client_a.summarize_contacts(cx_a).outgoing_requests,
        &["user_b"]
    );
    assert_eq!(
        client_b.summarize_contacts(cx_b).incoming_requests,
        &["user_a", "user_c"]
    );
    assert_eq!(
        client_c.summarize_contacts(cx_c).outgoing_requests,
        &["user_b"]
    );

    // User B accepts the request from user A.
    client_b
        .user_store
        .update(cx_b, |store, cx| {
            store.respond_to_contact_request(client_a.user_id().unwrap(), true, cx)
        })
        .await
        .unwrap();

    deterministic.run_until_parked();

    // User B sees user A as their contact now in all client, and the incoming request from them is removed.
    let contacts_b = client_b.summarize_contacts(cx_b);
    assert_eq!(contacts_b.current, &["user_a"]);
    assert_eq!(contacts_b.incoming_requests, &["user_c"]);
    let contacts_b2 = client_b2.summarize_contacts(cx_b2);
    assert_eq!(contacts_b2.current, &["user_a"]);
    assert_eq!(contacts_b2.incoming_requests, &["user_c"]);

    // User A sees user B as their contact now in all clients, and the outgoing request to them is removed.
    let contacts_a = client_a.summarize_contacts(cx_a);
    assert_eq!(contacts_a.current, &["user_b"]);
    assert!(contacts_a.outgoing_requests.is_empty());
    let contacts_a2 = client_a2.summarize_contacts(cx_a2);
    assert_eq!(contacts_a2.current, &["user_b"]);
    assert!(contacts_a2.outgoing_requests.is_empty());

    // Contacts are present upon connecting (tested here via disconnect/reconnect)
    disconnect_and_reconnect(&client_a, cx_a).await;
    disconnect_and_reconnect(&client_b, cx_b).await;
    disconnect_and_reconnect(&client_c, cx_c).await;
    deterministic.run_until_parked();
    assert_eq!(client_a.summarize_contacts(cx_a).current, &["user_b"]);
    assert_eq!(client_b.summarize_contacts(cx_b).current, &["user_a"]);
    assert_eq!(
        client_b.summarize_contacts(cx_b).incoming_requests,
        &["user_c"]
    );
    assert!(client_c.summarize_contacts(cx_c).current.is_empty());
    assert_eq!(
        client_c.summarize_contacts(cx_c).outgoing_requests,
        &["user_b"]
    );

    // User B rejects the request from user C.
    client_b
        .user_store
        .update(cx_b, |store, cx| {
            store.respond_to_contact_request(client_c.user_id().unwrap(), false, cx)
        })
        .await
        .unwrap();

    deterministic.run_until_parked();

    // User B doesn't see user C as their contact, and the incoming request from them is removed.
    let contacts_b = client_b.summarize_contacts(cx_b);
    assert_eq!(contacts_b.current, &["user_a"]);
    assert!(contacts_b.incoming_requests.is_empty());
    let contacts_b2 = client_b2.summarize_contacts(cx_b2);
    assert_eq!(contacts_b2.current, &["user_a"]);
    assert!(contacts_b2.incoming_requests.is_empty());

    // User C doesn't see user B as their contact, and the outgoing request to them is removed.
    let contacts_c = client_c.summarize_contacts(cx_c);
    assert!(contacts_c.current.is_empty());
    assert!(contacts_c.outgoing_requests.is_empty());
    let contacts_c2 = client_c2.summarize_contacts(cx_c2);
    assert!(contacts_c2.current.is_empty());
    assert!(contacts_c2.outgoing_requests.is_empty());

    // Incoming/outgoing requests are not present upon connecting (tested here via disconnect/reconnect)
    disconnect_and_reconnect(&client_a, cx_a).await;
    disconnect_and_reconnect(&client_b, cx_b).await;
    disconnect_and_reconnect(&client_c, cx_c).await;
    deterministic.run_until_parked();
    assert_eq!(client_a.summarize_contacts(cx_a).current, &["user_b"]);
    assert_eq!(client_b.summarize_contacts(cx_b).current, &["user_a"]);
    assert!(client_b
        .summarize_contacts(cx_b)
        .incoming_requests
        .is_empty());
    assert!(client_c.summarize_contacts(cx_c).current.is_empty());
    assert!(client_c
        .summarize_contacts(cx_c)
        .outgoing_requests
        .is_empty());

    async fn disconnect_and_reconnect(client: &TestClient, cx: &mut TestAppContext) {
        client.disconnect(&cx.to_async()).unwrap();
        client.clear_contacts(cx).await;
        client
            .authenticate_and_connect(false, &cx.to_async())
            .await
            .unwrap();
    }
}

#[gpui::test(iterations = 10)]
async fn test_following(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_a.update(editor::init);
    cx_b.update(editor::init);

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "1.txt": "one\none\none",
                "2.txt": "two\ntwo\ntwo",
                "3.txt": "three\nthree\nthree",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| call.set_location(Some(&project_a), cx))
        .await
        .unwrap();

    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();

    // Client A opens some editors.
    let workspace_a = client_a.build_workspace(&project_a, cx_a);
    let pane_a = workspace_a.read_with(cx_a, |workspace, _| workspace.active_pane().clone());
    let editor_a1 = workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();
    let editor_a2 = workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "2.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    // Client B opens an editor.
    let workspace_b = client_b.build_workspace(&project_b, cx_b);
    let editor_b1 = workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    let client_a_id = project_b.read_with(cx_b, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });
    let client_b_id = project_a.read_with(cx_a, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });

    // When client B starts following client A, all visible view states are replicated to client B.
    editor_a1.update(cx_a, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([0..1]))
    });
    editor_a2.update(cx_a, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([2..3]))
    });
    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(client_a_id), cx)
                .unwrap()
        })
        .await
        .unwrap();

    let editor_b2 = workspace_b.read_with(cx_b, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<Editor>()
            .unwrap()
    });
    assert!(cx_b.read(|cx| editor_b2.is_focused(cx)));
    assert_eq!(
        editor_b2.read_with(cx_b, |editor, cx| editor.project_path(cx)),
        Some((worktree_id, "2.txt").into())
    );
    assert_eq!(
        editor_b2.read_with(cx_b, |editor, cx| editor.selections.ranges(cx)),
        vec![2..3]
    );
    assert_eq!(
        editor_b1.read_with(cx_b, |editor, cx| editor.selections.ranges(cx)),
        vec![0..1]
    );

    // When client A activates a different editor, client B does so as well.
    workspace_a.update(cx_a, |workspace, cx| {
        workspace.activate_item(&editor_a1, cx)
    });
    deterministic.run_until_parked();
    workspace_b.read_with(cx_b, |workspace, cx| {
        assert_eq!(workspace.active_item(cx).unwrap().id(), editor_b1.id());
    });

    // When client A opens a multibuffer, client B does so as well.
    let multibuffer_a = cx_a.add_model(|cx| {
        let buffer_a1 = project_a.update(cx, |project, cx| {
            project
                .get_open_buffer(&(worktree_id, "1.txt").into(), cx)
                .unwrap()
        });
        let buffer_a2 = project_a.update(cx, |project, cx| {
            project
                .get_open_buffer(&(worktree_id, "2.txt").into(), cx)
                .unwrap()
        });
        let mut result = MultiBuffer::new(0);
        result.push_excerpts(
            buffer_a1,
            [ExcerptRange {
                context: 0..3,
                primary: None,
            }],
            cx,
        );
        result.push_excerpts(
            buffer_a2,
            [ExcerptRange {
                context: 4..7,
                primary: None,
            }],
            cx,
        );
        result
    });
    let multibuffer_editor_a = workspace_a.update(cx_a, |workspace, cx| {
        let editor =
            cx.add_view(|cx| Editor::for_multibuffer(multibuffer_a, Some(project_a.clone()), cx));
        workspace.add_item(Box::new(editor.clone()), cx);
        editor
    });
    deterministic.run_until_parked();
    let multibuffer_editor_b = workspace_b.read_with(cx_b, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<Editor>()
            .unwrap()
    });
    assert_eq!(
        multibuffer_editor_a.read_with(cx_a, |editor, cx| editor.text(cx)),
        multibuffer_editor_b.read_with(cx_b, |editor, cx| editor.text(cx)),
    );

    // When client A navigates back and forth, client B does so as well.
    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace::Pane::go_back(workspace, None, cx)
        })
        .await;
    deterministic.run_until_parked();
    workspace_b.read_with(cx_b, |workspace, cx| {
        assert_eq!(workspace.active_item(cx).unwrap().id(), editor_b1.id());
    });

    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace::Pane::go_back(workspace, None, cx)
        })
        .await;
    deterministic.run_until_parked();
    workspace_b.read_with(cx_b, |workspace, cx| {
        assert_eq!(workspace.active_item(cx).unwrap().id(), editor_b2.id());
    });

    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace::Pane::go_forward(workspace, None, cx)
        })
        .await;
    deterministic.run_until_parked();
    workspace_b.read_with(cx_b, |workspace, cx| {
        assert_eq!(workspace.active_item(cx).unwrap().id(), editor_b1.id());
    });

    // Changes to client A's editor are reflected on client B.
    editor_a1.update(cx_a, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([1..1, 2..2]));
    });
    deterministic.run_until_parked();
    editor_b1.read_with(cx_b, |editor, cx| {
        assert_eq!(editor.selections.ranges(cx), &[1..1, 2..2]);
    });

    editor_a1.update(cx_a, |editor, cx| editor.set_text("TWO", cx));
    deterministic.run_until_parked();
    editor_b1.read_with(cx_b, |editor, cx| assert_eq!(editor.text(cx), "TWO"));

    editor_a1.update(cx_a, |editor, cx| {
        editor.change_selections(None, cx, |s| s.select_ranges([3..3]));
        editor.set_scroll_position(vec2f(0., 100.), cx);
    });
    deterministic.run_until_parked();
    editor_b1.read_with(cx_b, |editor, cx| {
        assert_eq!(editor.selections.ranges(cx), &[3..3]);
    });

    // After unfollowing, client B stops receiving updates from client A.
    workspace_b.update(cx_b, |workspace, cx| {
        workspace.unfollow(&workspace.active_pane().clone(), cx)
    });
    workspace_a.update(cx_a, |workspace, cx| {
        workspace.activate_item(&editor_a2, cx)
    });
    deterministic.run_until_parked();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, cx| workspace
            .active_item(cx)
            .unwrap()
            .id()),
        editor_b1.id()
    );

    // Client A starts following client B.
    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(client_b_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_a.read_with(cx_a, |workspace, _| workspace.leader_for_pane(&pane_a)),
        Some(client_b_id)
    );
    assert_eq!(
        workspace_a.read_with(cx_a, |workspace, cx| workspace
            .active_item(cx)
            .unwrap()
            .id()),
        editor_a1.id()
    );

    // Client B activates an external window, which causes a new screen-sharing item to be added to the pane.
    let display = MacOSDisplay::new();
    active_call_b
        .update(cx_b, |call, cx| call.set_location(None, cx))
        .await
        .unwrap();
    active_call_b
        .update(cx_b, |call, cx| {
            call.room().unwrap().update(cx, |room, cx| {
                room.set_display_sources(vec![display.clone()]);
                room.share_screen(cx)
            })
        })
        .await
        .unwrap();
    deterministic.run_until_parked();
    let shared_screen = workspace_a.read_with(cx_a, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<SharedScreen>()
            .unwrap()
    });

    // Client B activates Zed again, which causes the previous editor to become focused again.
    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    workspace_a.read_with(cx_a, |workspace, cx| {
        assert_eq!(workspace.active_item(cx).unwrap().id(), editor_a1.id())
    });

    // Client B activates a multibuffer that was created by following client A. Client A returns to that multibuffer.
    workspace_b.update(cx_b, |workspace, cx| {
        workspace.activate_item(&multibuffer_editor_b, cx)
    });
    deterministic.run_until_parked();
    workspace_a.read_with(cx_a, |workspace, cx| {
        assert_eq!(
            workspace.active_item(cx).unwrap().id(),
            multibuffer_editor_a.id()
        )
    });

    // Client B activates an external window again, and the previously-opened screen-sharing item
    // gets activated.
    active_call_b
        .update(cx_b, |call, cx| call.set_location(None, cx))
        .await
        .unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        workspace_a.read_with(cx_a, |workspace, cx| workspace
            .active_item(cx)
            .unwrap()
            .id()),
        shared_screen.id()
    );

    // Following interrupts when client B disconnects.
    client_b.disconnect(&cx_b.to_async()).unwrap();
    deterministic.run_until_parked();
    assert_eq!(
        workspace_a.read_with(cx_a, |workspace, _| workspace.leader_for_pane(&pane_a)),
        None
    );
}

#[gpui::test]
async fn test_following_tab_order(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    cx_a.update(editor::init);
    cx_b.update(editor::init);

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "1.txt": "one",
                "2.txt": "two",
                "3.txt": "three",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| call.set_location(Some(&project_a), cx))
        .await
        .unwrap();

    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();

    let workspace_a = client_a.build_workspace(&project_a, cx_a);
    let pane_a = workspace_a.read_with(cx_a, |workspace, _| workspace.active_pane().clone());

    let workspace_b = client_b.build_workspace(&project_b, cx_b);
    let pane_b = workspace_b.read_with(cx_b, |workspace, _| workspace.active_pane().clone());

    let client_b_id = project_a.read_with(cx_a, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });

    //Open 1, 3 in that order on client A
    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap();
    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "3.txt"), None, true, cx)
        })
        .await
        .unwrap();

    let pane_paths = |pane: &ViewHandle<workspace::Pane>, cx: &mut TestAppContext| {
        pane.update(cx, |pane, cx| {
            pane.items()
                .map(|item| {
                    item.project_path(cx)
                        .unwrap()
                        .path
                        .to_str()
                        .unwrap()
                        .to_owned()
                })
                .collect::<Vec<_>>()
        })
    };

    //Verify that the tabs opened in the order we expect
    assert_eq!(&pane_paths(&pane_a, cx_a), &["1.txt", "3.txt"]);

    //Follow client B as client A
    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(client_b_id), cx)
                .unwrap()
        })
        .await
        .unwrap();

    //Open just 2 on client B
    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "2.txt"), None, true, cx)
        })
        .await
        .unwrap();
    deterministic.run_until_parked();

    // Verify that newly opened followed file is at the end
    assert_eq!(&pane_paths(&pane_a, cx_a), &["1.txt", "3.txt", "2.txt"]);

    //Open just 1 on client B
    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap();
    assert_eq!(&pane_paths(&pane_b, cx_b), &["2.txt", "1.txt"]);
    deterministic.run_until_parked();

    // Verify that following into 1 did not reorder
    assert_eq!(&pane_paths(&pane_a, cx_a), &["1.txt", "3.txt", "2.txt"]);
}

#[gpui::test(iterations = 10)]
async fn test_peers_following_each_other(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_a.update(editor::init);
    cx_b.update(editor::init);

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    // Client A shares a project.
    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "1.txt": "one",
                "2.txt": "two",
                "3.txt": "three",
                "4.txt": "four",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| call.set_location(Some(&project_a), cx))
        .await
        .unwrap();
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    // Client B joins the project.
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();

    // Client A opens some editors.
    let workspace_a = client_a.build_workspace(&project_a, cx_a);
    let pane_a1 = workspace_a.read_with(cx_a, |workspace, _| workspace.active_pane().clone());
    let _editor_a1 = workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    // Client B opens an editor.
    let workspace_b = client_b.build_workspace(&project_b, cx_b);
    let pane_b1 = workspace_b.read_with(cx_b, |workspace, _| workspace.active_pane().clone());
    let _editor_b1 = workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "2.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    // Clients A and B follow each other in split panes
    workspace_a.update(cx_a, |workspace, cx| {
        workspace.split_pane(workspace.active_pane().clone(), SplitDirection::Right, cx);
        let pane_a1 = pane_a1.clone();
        cx.defer(move |workspace, _| {
            assert_ne!(*workspace.active_pane(), pane_a1);
        });
    });
    workspace_a
        .update(cx_a, |workspace, cx| {
            let leader_id = *project_a.read(cx).collaborators().keys().next().unwrap();
            workspace
                .toggle_follow(&workspace::ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    workspace_b.update(cx_b, |workspace, cx| {
        workspace.split_pane(workspace.active_pane().clone(), SplitDirection::Right, cx);
        let pane_b1 = pane_b1.clone();
        cx.defer(move |workspace, _| {
            assert_ne!(*workspace.active_pane(), pane_b1);
        });
    });
    workspace_b
        .update(cx_b, |workspace, cx| {
            let leader_id = *project_b.read(cx).collaborators().keys().next().unwrap();
            workspace
                .toggle_follow(&workspace::ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();

    workspace_a.update(cx_a, |workspace, cx| {
        workspace.activate_next_pane(cx);
    });
    // Wait for focus effects to be fully flushed
    workspace_a.update(cx_a, |workspace, _| {
        assert_eq!(*workspace.active_pane(), pane_a1);
    });

    workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "3.txt"), None, true, cx)
        })
        .await
        .unwrap();
    workspace_b.update(cx_b, |workspace, cx| {
        workspace.activate_next_pane(cx);
    });

    workspace_b
        .update(cx_b, |workspace, cx| {
            assert_eq!(*workspace.active_pane(), pane_b1);
            workspace.open_path((worktree_id, "4.txt"), None, true, cx)
        })
        .await
        .unwrap();
    cx_a.foreground().run_until_parked();

    // Ensure leader updates don't change the active pane of followers
    workspace_a.read_with(cx_a, |workspace, _| {
        assert_eq!(*workspace.active_pane(), pane_a1);
    });
    workspace_b.read_with(cx_b, |workspace, _| {
        assert_eq!(*workspace.active_pane(), pane_b1);
    });

    // Ensure peers following each other doesn't cause an infinite loop.
    assert_eq!(
        workspace_a.read_with(cx_a, |workspace, cx| workspace
            .active_item(cx)
            .unwrap()
            .project_path(cx)),
        Some((worktree_id, "3.txt").into())
    );
    workspace_a.update(cx_a, |workspace, cx| {
        assert_eq!(
            workspace.active_item(cx).unwrap().project_path(cx),
            Some((worktree_id, "3.txt").into())
        );
        workspace.activate_next_pane(cx);
    });

    workspace_a.update(cx_a, |workspace, cx| {
        assert_eq!(
            workspace.active_item(cx).unwrap().project_path(cx),
            Some((worktree_id, "4.txt").into())
        );
    });

    workspace_b.update(cx_b, |workspace, cx| {
        assert_eq!(
            workspace.active_item(cx).unwrap().project_path(cx),
            Some((worktree_id, "4.txt").into())
        );
        workspace.activate_next_pane(cx);
    });

    workspace_b.update(cx_b, |workspace, cx| {
        assert_eq!(
            workspace.active_item(cx).unwrap().project_path(cx),
            Some((worktree_id, "3.txt").into())
        );
    });
}

#[gpui::test(iterations = 10)]
async fn test_auto_unfollowing(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_a.update(editor::init);
    cx_b.update(editor::init);

    // 2 clients connect to a server.
    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);
    let active_call_b = cx_b.read(ActiveCall::global);

    // Client A shares a project.
    client_a
        .fs
        .insert_tree(
            "/a",
            json!({
                "1.txt": "one",
                "2.txt": "two",
                "3.txt": "three",
            }),
        )
        .await;
    let (project_a, worktree_id) = client_a.build_local_project("/a", cx_a).await;
    active_call_a
        .update(cx_a, |call, cx| call.set_location(Some(&project_a), cx))
        .await
        .unwrap();

    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();
    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    active_call_b
        .update(cx_b, |call, cx| call.set_location(Some(&project_b), cx))
        .await
        .unwrap();

    // Client A opens some editors.
    let workspace_a = client_a.build_workspace(&project_a, cx_a);
    let _editor_a1 = workspace_a
        .update(cx_a, |workspace, cx| {
            workspace.open_path((worktree_id, "1.txt"), None, true, cx)
        })
        .await
        .unwrap()
        .downcast::<Editor>()
        .unwrap();

    // Client B starts following client A.
    let workspace_b = client_b.build_workspace(&project_b, cx_b);
    let pane_b = workspace_b.read_with(cx_b, |workspace, _| workspace.active_pane().clone());
    let leader_id = project_b.read_with(cx_b, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });
    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );
    let editor_b2 = workspace_b.read_with(cx_b, |workspace, cx| {
        workspace
            .active_item(cx)
            .unwrap()
            .downcast::<Editor>()
            .unwrap()
    });

    // When client B moves, it automatically stops following client A.
    editor_b2.update(cx_b, |editor, cx| editor.move_right(&editor::MoveRight, cx));
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        None
    );

    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );

    // When client B edits, it automatically stops following client A.
    editor_b2.update(cx_b, |editor, cx| editor.insert("X", cx));
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        None
    );

    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );

    // When client B scrolls, it automatically stops following client A.
    editor_b2.update(cx_b, |editor, cx| {
        editor.set_scroll_position(vec2f(0., 3.), cx)
    });
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        None
    );

    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace
                .toggle_follow(&ToggleFollow(leader_id), cx)
                .unwrap()
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );

    // When client B activates a different pane, it continues following client A in the original pane.
    workspace_b.update(cx_b, |workspace, cx| {
        workspace.split_pane(pane_b.clone(), SplitDirection::Right, cx)
    });
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );

    workspace_b.update(cx_b, |workspace, cx| workspace.activate_next_pane(cx));
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        Some(leader_id)
    );

    // When client B activates a different item in the original pane, it automatically stops following client A.
    workspace_b
        .update(cx_b, |workspace, cx| {
            workspace.open_path((worktree_id, "2.txt"), None, true, cx)
        })
        .await
        .unwrap();
    assert_eq!(
        workspace_b.read_with(cx_b, |workspace, _| workspace.leader_for_pane(&pane_b)),
        None
    );
}

#[gpui::test(iterations = 10)]
async fn test_peers_simultaneously_following_each_other(
    deterministic: Arc<Deterministic>,
    cx_a: &mut TestAppContext,
    cx_b: &mut TestAppContext,
) {
    deterministic.forbid_parking();
    cx_a.update(editor::init);
    cx_b.update(editor::init);

    let mut server = TestServer::start(&deterministic).await;
    let client_a = server.create_client(cx_a, "user_a").await;
    let client_b = server.create_client(cx_b, "user_b").await;
    server
        .create_room(&mut [(&client_a, cx_a), (&client_b, cx_b)])
        .await;
    let active_call_a = cx_a.read(ActiveCall::global);

    client_a.fs.insert_tree("/a", json!({})).await;
    let (project_a, _) = client_a.build_local_project("/a", cx_a).await;
    let workspace_a = client_a.build_workspace(&project_a, cx_a);
    let project_id = active_call_a
        .update(cx_a, |call, cx| call.share_project(project_a.clone(), cx))
        .await
        .unwrap();

    let project_b = client_b.build_remote_project(project_id, cx_b).await;
    let workspace_b = client_b.build_workspace(&project_b, cx_b);

    deterministic.run_until_parked();
    let client_a_id = project_b.read_with(cx_b, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });
    let client_b_id = project_a.read_with(cx_a, |project, _| {
        project.collaborators().values().next().unwrap().peer_id
    });

    let a_follow_b = workspace_a.update(cx_a, |workspace, cx| {
        workspace
            .toggle_follow(&ToggleFollow(client_b_id), cx)
            .unwrap()
    });
    let b_follow_a = workspace_b.update(cx_b, |workspace, cx| {
        workspace
            .toggle_follow(&ToggleFollow(client_a_id), cx)
            .unwrap()
    });

    futures::try_join!(a_follow_b, b_follow_a).unwrap();
    workspace_a.read_with(cx_a, |workspace, _| {
        assert_eq!(
            workspace.leader_for_pane(workspace.active_pane()),
            Some(client_b_id)
        );
    });
    workspace_b.read_with(cx_b, |workspace, _| {
        assert_eq!(
            workspace.leader_for_pane(workspace.active_pane()),
            Some(client_a_id)
        );
    });
}

#[gpui::test(iterations = 100)]
async fn test_random_collaboration(
    cx: &mut TestAppContext,
    deterministic: Arc<Deterministic>,
    rng: StdRng,
) {
    deterministic.forbid_parking();
    let rng = Arc::new(Mutex::new(rng));

    let max_peers = env::var("MAX_PEERS")
        .map(|i| i.parse().expect("invalid `MAX_PEERS` variable"))
        .unwrap_or(5);

    let max_operations = env::var("OPERATIONS")
        .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
        .unwrap_or(10);

    let mut server = TestServer::start(&deterministic).await;
    let db = server.app_state.db.clone();

    let mut available_guests = Vec::new();
    for ix in 0..max_peers {
        let username = format!("guest-{}", ix + 1);
        let user_id = db
            .create_user(
                &format!("{username}@example.com"),
                false,
                NewUserParams {
                    github_login: username.clone(),
                    github_user_id: (ix + 1) as i32,
                    invite_count: 0,
                },
            )
            .await
            .unwrap()
            .user_id;
        available_guests.push((user_id, username));
    }

    for (ix, (user_id_a, _)) in available_guests.iter().enumerate() {
        for (user_id_b, _) in &available_guests[ix + 1..] {
            server
                .app_state
                .db
                .send_contact_request(*user_id_a, *user_id_b)
                .await
                .unwrap();
            server
                .app_state
                .db
                .respond_to_contact_request(*user_id_b, *user_id_a, true)
                .await
                .unwrap();
        }
    }

    let mut clients = Vec::new();
    let mut user_ids = Vec::new();
    let mut op_start_signals = Vec::new();
    let mut next_entity_id = 100000;

    let mut operations = 0;
    while operations < max_operations {
        let distribution = rng.lock().gen_range(0..100);
        match distribution {
            0..=19 if !available_guests.is_empty() => {
                let guest_ix = rng.lock().gen_range(0..available_guests.len());
                let (_, guest_username) = available_guests.remove(guest_ix);
                log::info!("Adding new connection for {}", guest_username);
                next_entity_id += 100000;
                let mut guest_cx = TestAppContext::new(
                    cx.foreground_platform(),
                    cx.platform(),
                    deterministic.build_foreground(next_entity_id),
                    deterministic.build_background(),
                    cx.font_cache(),
                    cx.leak_detector(),
                    next_entity_id,
                    cx.function_name.clone(),
                );

                let op_start_signal = futures::channel::mpsc::unbounded();
                let guest = server.create_client(&mut guest_cx, &guest_username).await;
                user_ids.push(guest.current_user_id(&guest_cx));
                op_start_signals.push(op_start_signal.0);
                clients.push(guest_cx.foreground().spawn(guest.simulate(
                    guest_username.clone(),
                    op_start_signal.1,
                    rng.clone(),
                    guest_cx,
                )));

                log::info!("Added connection for {}", guest_username);
                operations += 1;
            }
            20..=24 if clients.len() > 1 => {
                let guest_ix = rng.lock().gen_range(1..clients.len());
                log::info!(
                    "Simulating full disconnection of guest {}",
                    user_ids[guest_ix]
                );
                let removed_guest_id = user_ids.remove(guest_ix);
                let user_connection_ids = server
                    .connection_pool
                    .lock()
                    .user_connection_ids(removed_guest_id)
                    .collect::<Vec<_>>();
                assert_eq!(user_connection_ids.len(), 1);
                let removed_peer_id = PeerId(user_connection_ids[0].0);
                let guest = clients.remove(guest_ix);
                op_start_signals.remove(guest_ix);
                server.forbid_connections();
                server.disconnect_client(removed_peer_id);
                deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
                deterministic.start_waiting();
                log::info!("Waiting for guest {} to exit...", removed_guest_id);
                let (guest, mut guest_cx) = guest.await;
                deterministic.finish_waiting();
                server.allow_connections();

                for project in &guest.remote_projects {
                    project.read_with(&guest_cx, |project, _| assert!(project.is_read_only()));
                }
                for user_id in &user_ids {
                    let contacts = server.app_state.db.get_contacts(*user_id).await.unwrap();
                    let pool = server.connection_pool.lock();
                    for contact in contacts {
                        if let db::Contact::Accepted { user_id, .. } = contact {
                            if pool.is_user_online(user_id) {
                                assert_ne!(
                                    user_id, removed_guest_id,
                                    "removed guest is still a contact of another peer"
                                );
                            }
                        }
                    }
                }

                log::info!("{} removed", guest.username);
                available_guests.push((removed_guest_id, guest.username.clone()));
                guest_cx.update(|cx| {
                    cx.clear_globals();
                    drop(guest);
                });

                operations += 1;
            }
            25..=29 if clients.len() > 1 => {
                let guest_ix = rng.lock().gen_range(1..clients.len());
                let user_id = user_ids[guest_ix];
                log::info!("Simulating temporary disconnection of guest {}", user_id);
                let user_connection_ids = server
                    .connection_pool
                    .lock()
                    .user_connection_ids(user_id)
                    .collect::<Vec<_>>();
                assert_eq!(user_connection_ids.len(), 1);
                let peer_id = PeerId(user_connection_ids[0].0);
                server.disconnect_client(peer_id);
                deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
                operations += 1;
            }
            30..=34 => {
                log::info!("Simulating server restart");
                server.teardown();
                deterministic.advance_clock(RECEIVE_TIMEOUT + RECONNECT_TIMEOUT);
                server.start().await.unwrap();
                deterministic.advance_clock(CLEANUP_TIMEOUT);
            }
            _ if !op_start_signals.is_empty() => {
                while operations < max_operations && rng.lock().gen_bool(0.7) {
                    op_start_signals
                        .choose(&mut *rng.lock())
                        .unwrap()
                        .unbounded_send(())
                        .unwrap();
                    operations += 1;
                }

                if rng.lock().gen_bool(0.8) {
                    deterministic.run_until_parked();
                }
            }
            _ => {}
        }
    }

    drop(op_start_signals);
    deterministic.start_waiting();
    let clients = futures::future::join_all(clients).await;
    deterministic.finish_waiting();
    deterministic.run_until_parked();

    for (guest_client, guest_cx) in &clients {
        for guest_project in &guest_client.remote_projects {
            guest_project.read_with(guest_cx, |guest_project, cx| {
                let host_project = clients.iter().find_map(|(client, cx)| {
                    let project = client.local_projects.iter().find(|host_project| {
                        host_project.read_with(cx, |host_project, _| {
                            host_project.remote_id() == guest_project.remote_id()
                        })
                    })?;
                    Some((project, cx))
                });

                if !guest_project.is_read_only() {
                    if let Some((host_project, host_cx)) = host_project {
                        let host_worktree_snapshots =
                            host_project.read_with(host_cx, |host_project, cx| {
                                host_project
                                    .worktrees(cx)
                                    .map(|worktree| {
                                        let worktree = worktree.read(cx);
                                        (worktree.id(), worktree.snapshot())
                                    })
                                    .collect::<BTreeMap<_, _>>()
                            });
                        let guest_worktree_snapshots = guest_project
                            .worktrees(cx)
                            .map(|worktree| {
                                let worktree = worktree.read(cx);
                                (worktree.id(), worktree.snapshot())
                            })
                            .collect::<BTreeMap<_, _>>();

                        assert_eq!(
                            guest_worktree_snapshots.keys().collect::<Vec<_>>(),
                            host_worktree_snapshots.keys().collect::<Vec<_>>(),
                            "{} has different worktrees than the host",
                            guest_client.username
                        );

                        for (id, host_snapshot) in &host_worktree_snapshots {
                            let guest_snapshot = &guest_worktree_snapshots[id];
                            assert_eq!(
                                guest_snapshot.root_name(),
                                host_snapshot.root_name(),
                                "{} has different root name than the host for worktree {}",
                                guest_client.username,
                                id
                            );
                            assert_eq!(
                                guest_snapshot.abs_path(),
                                host_snapshot.abs_path(),
                                "{} has different abs path than the host for worktree {}",
                                guest_client.username,
                                id
                            );
                            assert_eq!(
                                guest_snapshot.entries(false).collect::<Vec<_>>(),
                                host_snapshot.entries(false).collect::<Vec<_>>(),
                                "{} has different snapshot than the host for worktree {}",
                                guest_client.username,
                                id
                            );
                            assert_eq!(guest_snapshot.scan_id(), host_snapshot.scan_id());
                        }
                    }
                }

                guest_project.check_invariants(cx);
            });
        }

        for (guest_project, guest_buffers) in &guest_client.buffers {
            let project_id = if guest_project.read_with(guest_cx, |project, _| {
                project.is_local() || project.is_read_only()
            }) {
                continue;
            } else {
                guest_project
                    .read_with(guest_cx, |project, _| project.remote_id())
                    .unwrap()
            };

            let host_project = clients.iter().find_map(|(client, cx)| {
                let project = client.local_projects.iter().find(|host_project| {
                    host_project.read_with(cx, |host_project, _| {
                        host_project.remote_id() == Some(project_id)
                    })
                })?;
                Some((project, cx))
            });

            let (host_project, host_cx) = if let Some((host_project, host_cx)) = host_project {
                (host_project, host_cx)
            } else {
                continue;
            };

            for guest_buffer in guest_buffers {
                let buffer_id = guest_buffer.read_with(guest_cx, |buffer, _| buffer.remote_id());
                let host_buffer = host_project.read_with(host_cx, |project, cx| {
                    project.buffer_for_id(buffer_id, cx).unwrap_or_else(|| {
                        panic!(
                            "host does not have buffer for guest:{}, peer:{:?}, id:{}",
                            guest_client.username,
                            guest_client.peer_id(),
                            buffer_id
                        )
                    })
                });
                let path = host_buffer
                    .read_with(host_cx, |buffer, cx| buffer.file().unwrap().full_path(cx));

                assert_eq!(
                    guest_buffer.read_with(guest_cx, |buffer, _| buffer.deferred_ops_len()),
                    0,
                    "{}, buffer {}, path {:?} has deferred operations",
                    guest_client.username,
                    buffer_id,
                    path,
                );
                assert_eq!(
                    guest_buffer.read_with(guest_cx, |buffer, _| buffer.text()),
                    host_buffer.read_with(host_cx, |buffer, _| buffer.text()),
                    "{}, buffer {}, path {:?}, differs from the host's buffer",
                    guest_client.username,
                    buffer_id,
                    path
                );
            }
        }
    }

    for (client, mut cx) in clients {
        cx.update(|cx| {
            cx.clear_globals();
            drop(client);
        });
    }
}

struct TestServer {
    app_state: Arc<AppState>,
    server: Arc<Server>,
    connection_killers: Arc<Mutex<HashMap<PeerId, Arc<AtomicBool>>>>,
    forbid_connections: Arc<AtomicBool>,
    _test_db: TestDb,
    test_live_kit_server: Arc<live_kit_client::TestServer>,
}

impl TestServer {
    async fn start(deterministic: &Arc<Deterministic>) -> Self {
        static NEXT_LIVE_KIT_SERVER_ID: AtomicUsize = AtomicUsize::new(0);

        let use_postgres = env::var("USE_POSTGRES").ok();
        let use_postgres = use_postgres.as_deref();
        let test_db = if use_postgres == Some("true") || use_postgres == Some("1") {
            TestDb::postgres(deterministic.build_background())
        } else {
            TestDb::sqlite(deterministic.build_background())
        };
        let live_kit_server_id = NEXT_LIVE_KIT_SERVER_ID.fetch_add(1, SeqCst);
        let live_kit_server = live_kit_client::TestServer::create(
            format!("http://livekit.{}.test", live_kit_server_id),
            format!("devkey-{}", live_kit_server_id),
            format!("secret-{}", live_kit_server_id),
            deterministic.build_background(),
        )
        .unwrap();
        let app_state = Self::build_app_state(&test_db, &live_kit_server).await;
        let server = Server::new(
            app_state.clone(),
            Executor::Deterministic(deterministic.build_background()),
        );
        server.start().await.unwrap();
        // Advance clock to ensure the server's cleanup task is finished.
        deterministic.advance_clock(CLEANUP_TIMEOUT);
        Self {
            app_state,
            server,
            connection_killers: Default::default(),
            forbid_connections: Default::default(),
            _test_db: test_db,
            test_live_kit_server: live_kit_server,
        }
    }

    fn teardown(&self) {
        self.server.teardown();
        self.app_state.db.reset();
    }

    async fn create_client(&mut self, cx: &mut TestAppContext, name: &str) -> TestClient {
        cx.update(|cx| {
            cx.set_global(HomeDir(Path::new("/tmp/").to_path_buf()));

            let mut settings = Settings::test(cx);
            settings.projects_online_by_default = false;
            cx.set_global(settings);
        });

        let http = FakeHttpClient::with_404_response();
        let user_id = if let Ok(Some(user)) = self
            .app_state
            .db
            .get_user_by_github_account(name, None)
            .await
        {
            user.id
        } else {
            self.app_state
                .db
                .create_user(
                    &format!("{name}@example.com"),
                    false,
                    NewUserParams {
                        github_login: name.into(),
                        github_user_id: 0,
                        invite_count: 0,
                    },
                )
                .await
                .expect("creating user failed")
                .user_id
        };
        let client_name = name.to_string();
        let mut client = cx.read(|cx| Client::new(http.clone(), cx));
        let server = self.server.clone();
        let db = self.app_state.db.clone();
        let connection_killers = self.connection_killers.clone();
        let forbid_connections = self.forbid_connections.clone();

        Arc::get_mut(&mut client)
            .unwrap()
            .set_id(user_id.0 as usize)
            .override_authenticate(move |cx| {
                cx.spawn(|_| async move {
                    let access_token = "the-token".to_string();
                    Ok(Credentials {
                        user_id: user_id.0 as u64,
                        access_token,
                    })
                })
            })
            .override_establish_connection(move |credentials, cx| {
                assert_eq!(credentials.user_id, user_id.0 as u64);
                assert_eq!(credentials.access_token, "the-token");

                let server = server.clone();
                let db = db.clone();
                let connection_killers = connection_killers.clone();
                let forbid_connections = forbid_connections.clone();
                let client_name = client_name.clone();
                cx.spawn(move |cx| async move {
                    if forbid_connections.load(SeqCst) {
                        Err(EstablishConnectionError::other(anyhow!(
                            "server is forbidding connections"
                        )))
                    } else {
                        let (client_conn, server_conn, killed) =
                            Connection::in_memory(cx.background());
                        let (connection_id_tx, connection_id_rx) = oneshot::channel();
                        let user = db
                            .get_user_by_id(user_id)
                            .await
                            .expect("retrieving user failed")
                            .unwrap();
                        cx.background()
                            .spawn(server.handle_connection(
                                server_conn,
                                client_name,
                                user,
                                Some(connection_id_tx),
                                Executor::Deterministic(cx.background()),
                            ))
                            .detach();
                        let connection_id = connection_id_rx.await.unwrap();
                        connection_killers
                            .lock()
                            .insert(PeerId(connection_id.0), killed);
                        Ok(client_conn)
                    }
                })
            });

        let fs = FakeFs::new(cx.background());
        let user_store = cx.add_model(|cx| UserStore::new(client.clone(), http, cx));
        let app_state = Arc::new(workspace::AppState {
            client: client.clone(),
            user_store: user_store.clone(),
            languages: Arc::new(LanguageRegistry::new(Task::ready(()))),
            themes: ThemeRegistry::new((), cx.font_cache()),
            fs: fs.clone(),
            build_window_options: Default::default,
            initialize_workspace: |_, _, _| unimplemented!(),
            dock_default_item_factory: |_, _| unimplemented!(),
        });

        Project::init(&client);
        cx.update(|cx| {
            workspace::init(app_state.clone(), cx);
            call::init(client.clone(), user_store.clone(), cx);
        });

        client
            .authenticate_and_connect(false, &cx.to_async())
            .await
            .unwrap();

        let client = TestClient {
            client,
            username: name.to_string(),
            local_projects: Default::default(),
            remote_projects: Default::default(),
            next_root_dir_id: 0,
            user_store,
            fs,
            language_registry: Arc::new(LanguageRegistry::test()),
            buffers: Default::default(),
        };
        client.wait_for_current_user(cx).await;
        client
    }

    fn disconnect_client(&self, peer_id: PeerId) {
        self.connection_killers
            .lock()
            .remove(&peer_id)
            .unwrap()
            .store(true, SeqCst);
    }

    fn forbid_connections(&self) {
        self.forbid_connections.store(true, SeqCst);
    }

    fn allow_connections(&self) {
        self.forbid_connections.store(false, SeqCst);
    }

    async fn make_contacts(&self, clients: &mut [(&TestClient, &mut TestAppContext)]) {
        for ix in 1..clients.len() {
            let (left, right) = clients.split_at_mut(ix);
            let (client_a, cx_a) = left.last_mut().unwrap();
            for (client_b, cx_b) in right {
                client_a
                    .user_store
                    .update(*cx_a, |store, cx| {
                        store.request_contact(client_b.user_id().unwrap(), cx)
                    })
                    .await
                    .unwrap();
                cx_a.foreground().run_until_parked();
                client_b
                    .user_store
                    .update(*cx_b, |store, cx| {
                        store.respond_to_contact_request(client_a.user_id().unwrap(), true, cx)
                    })
                    .await
                    .unwrap();
            }
        }
    }

    async fn create_room(&self, clients: &mut [(&TestClient, &mut TestAppContext)]) {
        self.make_contacts(clients).await;

        let (left, right) = clients.split_at_mut(1);
        let (_client_a, cx_a) = &mut left[0];
        let active_call_a = cx_a.read(ActiveCall::global);

        for (client_b, cx_b) in right {
            let user_id_b = client_b.current_user_id(*cx_b).to_proto();
            active_call_a
                .update(*cx_a, |call, cx| call.invite(user_id_b, None, cx))
                .await
                .unwrap();

            cx_b.foreground().run_until_parked();
            let active_call_b = cx_b.read(ActiveCall::global);
            active_call_b
                .update(*cx_b, |call, cx| call.accept_incoming(cx))
                .await
                .unwrap();
        }
    }

    async fn build_app_state(
        test_db: &TestDb,
        fake_server: &live_kit_client::TestServer,
    ) -> Arc<AppState> {
        Arc::new(AppState {
            db: test_db.db().clone(),
            live_kit_client: Some(Arc::new(fake_server.create_api_client())),
            config: Default::default(),
        })
    }
}

impl Deref for TestServer {
    type Target = Server;

    fn deref(&self) -> &Self::Target {
        &self.server
    }
}

impl Drop for TestServer {
    fn drop(&mut self) {
        self.server.teardown();
        self.test_live_kit_server.teardown().unwrap();
    }
}

struct TestClient {
    client: Arc<Client>,
    username: String,
    local_projects: Vec<ModelHandle<Project>>,
    remote_projects: Vec<ModelHandle<Project>>,
    next_root_dir_id: usize,
    pub user_store: ModelHandle<UserStore>,
    language_registry: Arc<LanguageRegistry>,
    fs: Arc<FakeFs>,
    buffers: HashMap<ModelHandle<Project>, HashSet<ModelHandle<language::Buffer>>>,
}

impl Deref for TestClient {
    type Target = Arc<Client>;

    fn deref(&self) -> &Self::Target {
        &self.client
    }
}

struct ContactsSummary {
    pub current: Vec<String>,
    pub outgoing_requests: Vec<String>,
    pub incoming_requests: Vec<String>,
}

impl TestClient {
    pub fn current_user_id(&self, cx: &TestAppContext) -> UserId {
        UserId::from_proto(
            self.user_store
                .read_with(cx, |user_store, _| user_store.current_user().unwrap().id),
        )
    }

    async fn wait_for_current_user(&self, cx: &TestAppContext) {
        let mut authed_user = self
            .user_store
            .read_with(cx, |user_store, _| user_store.watch_current_user());
        while authed_user.next().await.unwrap().is_none() {}
    }

    async fn clear_contacts(&self, cx: &mut TestAppContext) {
        self.user_store
            .update(cx, |store, _| store.clear_contacts())
            .await;
    }

    fn summarize_contacts(&self, cx: &TestAppContext) -> ContactsSummary {
        self.user_store.read_with(cx, |store, _| ContactsSummary {
            current: store
                .contacts()
                .iter()
                .map(|contact| contact.user.github_login.clone())
                .collect(),
            outgoing_requests: store
                .outgoing_contact_requests()
                .iter()
                .map(|user| user.github_login.clone())
                .collect(),
            incoming_requests: store
                .incoming_contact_requests()
                .iter()
                .map(|user| user.github_login.clone())
                .collect(),
        })
    }

    async fn build_local_project(
        &self,
        root_path: impl AsRef<Path>,
        cx: &mut TestAppContext,
    ) -> (ModelHandle<Project>, WorktreeId) {
        let project = cx.update(|cx| {
            Project::local(
                self.client.clone(),
                self.user_store.clone(),
                self.language_registry.clone(),
                self.fs.clone(),
                cx,
            )
        });
        let (worktree, _) = project
            .update(cx, |p, cx| {
                p.find_or_create_local_worktree(root_path, true, cx)
            })
            .await
            .unwrap();
        worktree
            .read_with(cx, |tree, _| tree.as_local().unwrap().scan_complete())
            .await;
        (project, worktree.read_with(cx, |tree, _| tree.id()))
    }

    async fn build_remote_project(
        &self,
        host_project_id: u64,
        guest_cx: &mut TestAppContext,
    ) -> ModelHandle<Project> {
        let project_b = guest_cx.spawn(|cx| {
            Project::remote(
                host_project_id,
                self.client.clone(),
                self.user_store.clone(),
                self.language_registry.clone(),
                FakeFs::new(cx.background()),
                cx,
            )
        });
        project_b.await.unwrap()
    }

    fn build_workspace(
        &self,
        project: &ModelHandle<Project>,
        cx: &mut TestAppContext,
    ) -> ViewHandle<Workspace> {
        let (_, root_view) = cx.add_window(|_| EmptyView);
        cx.add_view(&root_view, |cx| {
            Workspace::new(
                Default::default(),
                0,
                project.clone(),
                |_, _| unimplemented!(),
                cx,
            )
        })
    }

    pub async fn simulate(
        mut self,
        username: String,
        mut op_start_signal: futures::channel::mpsc::UnboundedReceiver<()>,
        rng: Arc<Mutex<StdRng>>,
        mut cx: TestAppContext,
    ) -> (Self, TestAppContext) {
        async fn tick(
            client: &mut TestClient,
            username: &str,
            rng: Arc<Mutex<StdRng>>,
            cx: &mut TestAppContext,
        ) -> anyhow::Result<()> {
            let active_call = cx.read(ActiveCall::global);
            if active_call.read_with(cx, |call, _| call.incoming().borrow().is_some()) {
                if rng.lock().gen() {
                    log::info!("{}: accepting incoming call", username);
                    active_call
                        .update(cx, |call, cx| call.accept_incoming(cx))
                        .await?;
                } else {
                    log::info!("{}: declining incoming call", username);
                    active_call.update(cx, |call, _| call.decline_incoming())?;
                }
            } else {
                let available_contacts = client.user_store.read_with(cx, |user_store, _| {
                    user_store
                        .contacts()
                        .iter()
                        .filter(|contact| contact.online && !contact.busy)
                        .cloned()
                        .collect::<Vec<_>>()
                });

                let distribution = rng.lock().gen_range(0..100);
                match distribution {
                    0..=29 if !available_contacts.is_empty() => {
                        let contact = available_contacts.choose(&mut *rng.lock()).unwrap();
                        log::info!("{}: inviting {}", username, contact.user.github_login);
                        active_call
                            .update(cx, |call, cx| call.invite(contact.user.id, None, cx))
                            .await?;
                    }
                    30..=39 if active_call.read_with(cx, |call, _| call.room().is_some()) => {
                        log::info!("{}: hanging up", username);
                        active_call.update(cx, |call, cx| call.hang_up(cx))?;
                    }
                    _ => {}
                }
            }

            let remote_projects =
                if let Some(room) = active_call.read_with(cx, |call, _| call.room().cloned()) {
                    room.read_with(cx, |room, _| {
                        room.remote_participants()
                            .values()
                            .flat_map(|participant| participant.projects.clone())
                            .collect::<Vec<_>>()
                    })
                } else {
                    Default::default()
                };
            let project = if remote_projects.is_empty() || rng.lock().gen() {
                if client.local_projects.is_empty() || rng.lock().gen() {
                    let dir_paths = client.fs.directories().await;
                    let local_project = if dir_paths.is_empty() || rng.lock().gen() {
                        let root_path = format!(
                            "/{}-root-{}",
                            username,
                            post_inc(&mut client.next_root_dir_id)
                        );
                        let root_path = Path::new(&root_path);
                        client.fs.create_dir(root_path).await.unwrap();
                        client
                            .fs
                            .create_file(&root_path.join("main.rs"), Default::default())
                            .await
                            .unwrap();
                        log::info!("{}: opening local project at {:?}", username, root_path);
                        client.build_local_project(root_path, cx).await.0
                    } else {
                        let root_path = dir_paths.choose(&mut *rng.lock()).unwrap();
                        log::info!("{}: opening local project at {:?}", username, root_path);
                        client.build_local_project(root_path, cx).await.0
                    };
                    client.local_projects.push(local_project.clone());
                    local_project
                } else {
                    client
                        .local_projects
                        .choose(&mut *rng.lock())
                        .unwrap()
                        .clone()
                }
            } else {
                if client.remote_projects.is_empty() || rng.lock().gen() {
                    let remote_project_id = remote_projects.choose(&mut *rng.lock()).unwrap().id;
                    let remote_project = if let Some(project) =
                        client.remote_projects.iter().find(|project| {
                            project.read_with(cx, |project, _| {
                                project.remote_id() == Some(remote_project_id)
                            })
                        }) {
                        project.clone()
                    } else {
                        log::info!("{}: opening remote project {}", username, remote_project_id);
                        let remote_project = Project::remote(
                            remote_project_id,
                            client.client.clone(),
                            client.user_store.clone(),
                            client.language_registry.clone(),
                            FakeFs::new(cx.background()),
                            cx.to_async(),
                        )
                        .await?;
                        client.remote_projects.push(remote_project.clone());
                        remote_project
                    };

                    remote_project
                } else {
                    client
                        .remote_projects
                        .choose(&mut *rng.lock())
                        .unwrap()
                        .clone()
                }
            };

            if active_call.read_with(cx, |call, _| call.room().is_some()) {
                if let Err(error) = active_call
                    .update(cx, |call, cx| call.share_project(project.clone(), cx))
                    .await
                {
                    log::error!("{}: error sharing project, {:?}", username, error);
                }
            }

            let buffers = client.buffers.entry(project.clone()).or_default();
            let buffer = if buffers.is_empty() || rng.lock().gen() {
                let worktree = if let Some(worktree) = project.read_with(cx, |project, cx| {
                    project
                        .worktrees(cx)
                        .filter(|worktree| {
                            let worktree = worktree.read(cx);
                            worktree.is_visible() && worktree.entries(false).any(|e| e.is_file())
                        })
                        .choose(&mut *rng.lock())
                }) {
                    worktree
                } else {
                    cx.background().simulate_random_delay().await;
                    return Ok(());
                };

                let (worktree_root_name, project_path) = worktree.read_with(cx, |worktree, _| {
                    let entry = worktree
                        .entries(false)
                        .filter(|e| e.is_file())
                        .choose(&mut *rng.lock())
                        .unwrap();
                    (
                        worktree.root_name().to_string(),
                        (worktree.id(), entry.path.clone()),
                    )
                });
                log::info!(
                    "{}: opening path {:?} in worktree {} ({})",
                    username,
                    project_path.1,
                    project_path.0,
                    worktree_root_name,
                );
                let buffer = project
                    .update(cx, |project, cx| {
                        project.open_buffer(project_path.clone(), cx)
                    })
                    .await?;
                log::info!(
                    "{}: opened path {:?} in worktree {} ({}) with buffer id {}",
                    username,
                    project_path.1,
                    project_path.0,
                    worktree_root_name,
                    buffer.read_with(cx, |buffer, _| buffer.remote_id())
                );
                buffers.insert(buffer.clone());
                buffer
            } else {
                buffers.iter().choose(&mut *rng.lock()).unwrap().clone()
            };

            let choice = rng.lock().gen_range(0..100);
            match choice {
                0..=9 => {
                    cx.update(|cx| {
                        log::info!(
                            "{}: dropping buffer {:?}",
                            username,
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        buffers.remove(&buffer);
                        drop(buffer);
                    });
                }
                10..=19 => {
                    let completions = project.update(cx, |project, cx| {
                        log::info!(
                            "{}: requesting completions for buffer {} ({:?})",
                            username,
                            buffer.read(cx).remote_id(),
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        let offset = rng.lock().gen_range(0..=buffer.read(cx).len());
                        project.completions(&buffer, offset, cx)
                    });
                    let completions = cx.background().spawn(async move {
                        completions
                            .await
                            .map_err(|err| anyhow!("completions request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching completions request", username);
                        cx.update(|cx| completions.detach_and_log_err(cx));
                    } else {
                        completions.await?;
                    }
                }
                20..=29 => {
                    let code_actions = project.update(cx, |project, cx| {
                        log::info!(
                            "{}: requesting code actions for buffer {} ({:?})",
                            username,
                            buffer.read(cx).remote_id(),
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        let range = buffer.read(cx).random_byte_range(0, &mut *rng.lock());
                        project.code_actions(&buffer, range, cx)
                    });
                    let code_actions = cx.background().spawn(async move {
                        code_actions
                            .await
                            .map_err(|err| anyhow!("code actions request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching code actions request", username);
                        cx.update(|cx| code_actions.detach_and_log_err(cx));
                    } else {
                        code_actions.await?;
                    }
                }
                30..=39 if buffer.read_with(cx, |buffer, _| buffer.is_dirty()) => {
                    let (requested_version, save) = buffer.update(cx, |buffer, cx| {
                        log::info!(
                            "{}: saving buffer {} ({:?})",
                            username,
                            buffer.remote_id(),
                            buffer.file().unwrap().full_path(cx)
                        );
                        (buffer.version(), buffer.save(cx))
                    });
                    let save = cx.background().spawn(async move {
                        let (saved_version, _, _) = save
                            .await
                            .map_err(|err| anyhow!("save request failed: {:?}", err))?;
                        assert!(saved_version.observed_all(&requested_version));
                        Ok::<_, anyhow::Error>(())
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching save request", username);
                        cx.update(|cx| save.detach_and_log_err(cx));
                    } else {
                        save.await?;
                    }
                }
                40..=44 => {
                    let prepare_rename = project.update(cx, |project, cx| {
                        log::info!(
                            "{}: preparing rename for buffer {} ({:?})",
                            username,
                            buffer.read(cx).remote_id(),
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        let offset = rng.lock().gen_range(0..=buffer.read(cx).len());
                        project.prepare_rename(buffer, offset, cx)
                    });
                    let prepare_rename = cx.background().spawn(async move {
                        prepare_rename
                            .await
                            .map_err(|err| anyhow!("prepare rename request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching prepare rename request", username);
                        cx.update(|cx| prepare_rename.detach_and_log_err(cx));
                    } else {
                        prepare_rename.await?;
                    }
                }
                45..=49 => {
                    let definitions = project.update(cx, |project, cx| {
                        log::info!(
                            "{}: requesting definitions for buffer {} ({:?})",
                            username,
                            buffer.read(cx).remote_id(),
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        let offset = rng.lock().gen_range(0..=buffer.read(cx).len());
                        project.definition(&buffer, offset, cx)
                    });
                    let definitions = cx.background().spawn(async move {
                        definitions
                            .await
                            .map_err(|err| anyhow!("definitions request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching definitions request", username);
                        cx.update(|cx| definitions.detach_and_log_err(cx));
                    } else {
                        buffers.extend(definitions.await?.into_iter().map(|loc| loc.target.buffer));
                    }
                }
                50..=54 => {
                    let highlights = project.update(cx, |project, cx| {
                        log::info!(
                            "{}: requesting highlights for buffer {} ({:?})",
                            username,
                            buffer.read(cx).remote_id(),
                            buffer.read(cx).file().unwrap().full_path(cx)
                        );
                        let offset = rng.lock().gen_range(0..=buffer.read(cx).len());
                        project.document_highlights(&buffer, offset, cx)
                    });
                    let highlights = cx.background().spawn(async move {
                        highlights
                            .await
                            .map_err(|err| anyhow!("highlights request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching highlights request", username);
                        cx.update(|cx| highlights.detach_and_log_err(cx));
                    } else {
                        highlights.await?;
                    }
                }
                55..=59 => {
                    let search = project.update(cx, |project, cx| {
                        let query = rng.lock().gen_range('a'..='z');
                        log::info!("{}: project-wide search {:?}", username, query);
                        project.search(SearchQuery::text(query, false, false), cx)
                    });
                    let search = cx.background().spawn(async move {
                        search
                            .await
                            .map_err(|err| anyhow!("search request failed: {:?}", err))
                    });
                    if rng.lock().gen_bool(0.3) {
                        log::info!("{}: detaching search request", username);
                        cx.update(|cx| search.detach_and_log_err(cx));
                    } else {
                        buffers.extend(search.await?.into_keys());
                    }
                }
                60..=79 => {
                    let worktree = project
                        .read_with(cx, |project, cx| {
                            project
                                .worktrees(cx)
                                .filter(|worktree| {
                                    let worktree = worktree.read(cx);
                                    worktree.is_visible()
                                        && worktree.entries(false).any(|e| e.is_file())
                                        && worktree.root_entry().map_or(false, |e| e.is_dir())
                                })
                                .choose(&mut *rng.lock())
                        })
                        .unwrap();
                    let (worktree_id, worktree_root_name) = worktree
                        .read_with(cx, |worktree, _| {
                            (worktree.id(), worktree.root_name().to_string())
                        });

                    let mut new_name = String::new();
                    for _ in 0..10 {
                        let letter = rng.lock().gen_range('a'..='z');
                        new_name.push(letter);
                    }

                    let is_dir = rng.lock().gen::<bool>();
                    let mut new_path = PathBuf::new();
                    new_path.push(new_name);
                    if !is_dir {
                        new_path.set_extension("rs");
                    }
                    log::info!(
                        "{}: creating {:?} in worktree {} ({})",
                        username,
                        new_path,
                        worktree_id,
                        worktree_root_name,
                    );
                    project
                        .update(cx, |project, cx| {
                            project.create_entry((worktree_id, new_path), is_dir, cx)
                        })
                        .unwrap()
                        .await?;
                }
                _ => {
                    buffer.update(cx, |buffer, cx| {
                        log::info!(
                            "{}: updating buffer {} ({:?})",
                            username,
                            buffer.remote_id(),
                            buffer.file().unwrap().full_path(cx)
                        );
                        if rng.lock().gen_bool(0.7) {
                            buffer.randomly_edit(&mut *rng.lock(), 5, cx);
                        } else {
                            buffer.randomly_undo_redo(&mut *rng.lock(), cx);
                        }
                    });
                }
            }

            Ok(())
        }

        // Setup language server
        let mut language = Language::new(
            LanguageConfig {
                name: "Rust".into(),
                path_suffixes: vec!["rs".to_string()],
                ..Default::default()
            },
            None,
        );
        let _fake_language_servers = language
            .set_fake_lsp_adapter(Arc::new(FakeLspAdapter {
                name: "the-fake-language-server",
                capabilities: lsp::LanguageServer::full_capabilities(),
                initializer: Some(Box::new({
                    let rng = rng.clone();
                    let fs = self.fs.clone();
                    move |fake_server: &mut FakeLanguageServer| {
                        fake_server.handle_request::<lsp::request::Completion, _, _>(
                            |_, _| async move {
                                Ok(Some(lsp::CompletionResponse::Array(vec![
                                    lsp::CompletionItem {
                                        text_edit: Some(lsp::CompletionTextEdit::Edit(
                                            lsp::TextEdit {
                                                range: lsp::Range::new(
                                                    lsp::Position::new(0, 0),
                                                    lsp::Position::new(0, 0),
                                                ),
                                                new_text: "the-new-text".to_string(),
                                            },
                                        )),
                                        ..Default::default()
                                    },
                                ])))
                            },
                        );

                        fake_server.handle_request::<lsp::request::CodeActionRequest, _, _>(
                            |_, _| async move {
                                Ok(Some(vec![lsp::CodeActionOrCommand::CodeAction(
                                    lsp::CodeAction {
                                        title: "the-code-action".to_string(),
                                        ..Default::default()
                                    },
                                )]))
                            },
                        );

                        fake_server.handle_request::<lsp::request::PrepareRenameRequest, _, _>(
                            |params, _| async move {
                                Ok(Some(lsp::PrepareRenameResponse::Range(lsp::Range::new(
                                    params.position,
                                    params.position,
                                ))))
                            },
                        );

                        fake_server.handle_request::<lsp::request::GotoDefinition, _, _>({
                            let fs = fs.clone();
                            let rng = rng.clone();
                            move |_, _| {
                                let fs = fs.clone();
                                let rng = rng.clone();
                                async move {
                                    let files = fs.files().await;
                                    let mut rng = rng.lock();
                                    let count = rng.gen_range::<usize, _>(1..3);
                                    let files = (0..count)
                                        .map(|_| files.choose(&mut *rng).unwrap())
                                        .collect::<Vec<_>>();
                                    log::info!("LSP: Returning definitions in files {:?}", &files);
                                    Ok(Some(lsp::GotoDefinitionResponse::Array(
                                        files
                                            .into_iter()
                                            .map(|file| lsp::Location {
                                                uri: lsp::Url::from_file_path(file).unwrap(),
                                                range: Default::default(),
                                            })
                                            .collect(),
                                    )))
                                }
                            }
                        });

                        fake_server.handle_request::<lsp::request::DocumentHighlightRequest, _, _>(
                            {
                                let rng = rng.clone();
                                move |_, _| {
                                    let mut highlights = Vec::new();
                                    let highlight_count = rng.lock().gen_range(1..=5);
                                    for _ in 0..highlight_count {
                                        let start_row = rng.lock().gen_range(0..100);
                                        let start_column = rng.lock().gen_range(0..100);
                                        let start = PointUtf16::new(start_row, start_column);
                                        let end_row = rng.lock().gen_range(0..100);
                                        let end_column = rng.lock().gen_range(0..100);
                                        let end = PointUtf16::new(end_row, end_column);
                                        let range =
                                            if start > end { end..start } else { start..end };
                                        highlights.push(lsp::DocumentHighlight {
                                            range: range_to_lsp(range.clone()),
                                            kind: Some(lsp::DocumentHighlightKind::READ),
                                        });
                                    }
                                    highlights.sort_unstable_by_key(|highlight| {
                                        (highlight.range.start, highlight.range.end)
                                    });
                                    async move { Ok(Some(highlights)) }
                                }
                            },
                        );
                    }
                })),
                ..Default::default()
            }))
            .await;
        self.language_registry.add(Arc::new(language));

        while op_start_signal.next().await.is_some() {
            if let Err(error) = tick(&mut self, &username, rng.clone(), &mut cx).await {
                log::error!("{} error: {:?}", username, error);
            }

            cx.background().simulate_random_delay().await;
        }
        log::info!("{}: done", username);

        (self, cx)
    }
}

impl Drop for TestClient {
    fn drop(&mut self) {
        self.client.tear_down();
    }
}

#[derive(Debug, Eq, PartialEq)]
struct RoomParticipants {
    remote: Vec<String>,
    pending: Vec<String>,
}

fn room_participants(room: &ModelHandle<Room>, cx: &mut TestAppContext) -> RoomParticipants {
    room.read_with(cx, |room, _| {
        let mut remote = room
            .remote_participants()
            .iter()
            .map(|(_, participant)| participant.user.github_login.clone())
            .collect::<Vec<_>>();
        let mut pending = room
            .pending_participants()
            .iter()
            .map(|user| user.github_login.clone())
            .collect::<Vec<_>>();
        remote.sort();
        pending.sort();
        RoomParticipants { remote, pending }
    })
}