Add command palette tests and simulate_keystrokes

crates/gpui2/src/action.rs

@@ -54,6 +54,9 @@ pub trait Action: std::fmt::Debug + 'static {
     where
         Self: Sized;
     fn build(value: Option<serde_json::Value>) -> Result<Box<dyn Action>>
+    where
+        Self: Sized;
+    fn is_registered() -> bool
     where
         Self: Sized;
 
@@ -88,6 +91,14 @@ where
         Ok(Box::new(action))
     }
 
+    fn is_registered() -> bool {
+        ACTION_REGISTRY
+            .read()
+            .names_by_type_id
+            .get(&TypeId::of::<A>())
+            .is_some()
+    }
+
     fn partial_eq(&self, action: &dyn Action) -> bool {
         action
             .as_any()