app task

src/textual/app.py

@@ -2099,7 +2099,7 @@ class App(Generic[ReturnType], DOMNode):
 
         # Launch the app in the "background"
 
-        app_task = create_task(run_app(app), name=f"run_test {app}")
+        self._task = app_task = create_task(run_app(app), name=f"run_test {app}")
 
         # Wait until the app has performed all startup routines.
         await app_ready_event.wait()

tests/test_reactive.py

@@ -545,7 +545,7 @@ async def test_async_reactive_watch_callbacks_go_on_the_watcher():
         def update(self):
             self.holder.attr = "hello world"
 
-        async def callback(self):
+        def callback(self):
             nonlocal from_app
             from_app = True