adding a warmup request

Author: HKalbasi

crates/rust-analyzer/tests/slow-tests/main.rs

@@ -735,18 +735,29 @@ fn main() {
     .server()
     .wait_until_workspace_is_loaded();
 
-    // For some reason, `wait_until_workspace_is_loaded` doesn't wait for loading non rs
-    // files, so here we sleep to make sure test will pass
-    sleep(Duration::from_secs(1));
 
     let checker = |line, hover: &str| {
-        let res = server.send_request::<HoverRequest>(HoverParams {
+        let params = HoverParams {
             text_document_position_params: TextDocumentPositionParams::new(
                 server.doc_id("src/main.rs"),
                 Position::new(line, 10),
             ),
             work_done_progress_params: Default::default(),
-        });
+        };
+
+
+        // This hover request will trigger the macro expanding, which will ask
+        // the handle to watch the missing file. Answer of the actual hover request
+        // might become ready before the file is being read. By sending a warmup
+        // request we make sure that this race condition won't make problem for
+        // this test.
+        //
+        // In practice this is not a problem because other things like inlayHint will
+        // trigger macro expansion.
+        server.send_request::<HoverRequest>(params.clone());
+        sleep(Duration::from_millis(1));
+
+        let res = server.send_request::<HoverRequest>(params);
         let res = res.to_string();
         assert!(
             res.contains(hover),