windows: Fix tests on Windows (#22616)

Release Notes:

- N/A

---------

Co-authored-by: Mikayla <mikayla.c.maki@gmail.com>

crates/copilot/src/copilot.rs

@@ -1061,6 +1061,7 @@ async fn get_copilot_lsp(http: Arc<dyn HttpClient>) -> anyhow::Result<PathBuf> {
 mod tests {
     use super::*;
     use gpui::TestAppContext;
+    use util::path;
 
     #[gpui::test(iterations = 10)]
     async fn test_buffer_management(cx: &mut TestAppContext) {
@@ -1123,7 +1124,7 @@ mod tests {
         buffer_1.update(cx, |buffer, cx| {
             buffer.file_updated(
                 Arc::new(File {
-                    abs_path: "/root/child/buffer-1".into(),
+                    abs_path: path!("/root/child/buffer-1").into(),
                     path: Path::new("child/buffer-1").into(),
                 }),
                 cx,
@@ -1136,7 +1137,7 @@ mod tests {
                 text_document: lsp::TextDocumentIdentifier::new(buffer_1_uri),
             }
         );
-        let buffer_1_uri = lsp::Url::from_file_path("/root/child/buffer-1").unwrap();
+        let buffer_1_uri = lsp::Url::from_file_path(path!("/root/child/buffer-1")).unwrap();
         assert_eq!(
             lsp.receive_notification::<lsp::notification::DidOpenTextDocument>()
                 .await,