Fix random fail in runtime::tokio::tests::test_spawn_and_abort (#10632)

this seems to be caused by non deterministic polling behaviour

Signed-off-by: Robert Kruszewski <github@robertk.io>

Author: robert3005

vortex-io/src/runtime/tokio.rs

@@ -198,26 +198,30 @@ mod tests {
         let runtime = TokioRuntime::from(tokio_rt.handle());
 
         let counter = Arc::new(AtomicUsize::new(0));
-        let c = Arc::clone(&counter);
+        let task_counter = Arc::clone(&counter);
 
-        // Create a channel to ensure the future doesn't complete immediately
-        let (send, recv) = oneshot::channel::<()>();
+        let (started_send, started_recv) = oneshot::channel::<()>();
+        let (mut release_send, release_recv) = oneshot::channel::<()>();
 
-        let (done_send, done_recv) = oneshot::channel::<()>();
-        let fut = async move {
-            let _done = done_send;
-            let _ = recv.await;
-            c.fetch_add(1, Ordering::SeqCst);
+        let future = async move {
+            started_send
+                .send(())
+                .expect("test retains the startup receiver");
+
+            let _ = release_recv.await;
+            task_counter.fetch_add(1, Ordering::SeqCst);
         };
-        let task = runtime.handle().spawn(fut.boxed());
-        drop(task);
+        let task = runtime.handle().spawn(future.boxed());
 
-        // Aborting is asynchronous. Keep the future blocked until cancellation finishes
-        // so it cannot complete during an in-flight poll.
         tokio_rt
-            .block_on(done_recv)
-            .expect_err("task has terminated");
-        assert!(send.send(()).is_err());
+            .block_on(started_recv)
+            .expect("spawned task must signal startup");
+
+        drop(task);
+
+        // Keeping the sender open without sending prevents normal completion.
+        tokio_rt.block_on(release_send.closed());
+
         assert_eq!(counter.load(Ordering::SeqCst), 0);
     }
 }