Improve test case

Author: iaalm

Lib/asyncio/futures.py

@@ -365,25 +365,6 @@ def _copy_future_state(source, dest):
     else:
         dest.set_result(result)
 
-
-def _cancel_future_in_loop(fut, loop, timeout=None):
-    """Cancel a future in (maybe another) event loop.
-
-    We need to check loop is not running loop to avoid dead lock.
-    """
-    if loop is None or loop is events._get_running_loop():
-        return fut.cancel()
-    cancel_fut = concurrent.futures.Future()
-    def _cancel():
-        try:
-            result = fut.cancel()
-            cancel_fut.set_result(result)
-        except BaseException as exc:
-            cancel_fut.set_exception(exc)
-    loop.call_soon_threadsafe(_cancel)
-    return cancel_fut.result(timeout=timeout)
-
-
 def _chain_future(source, destination):
     """Chain two futures so that when one completes, so does the other.
 
@@ -408,7 +389,10 @@ def _set_state(future, other):
 
     def _call_check_cancel(destination):
         if destination.cancelled():
-            _cancel_future_in_loop(source, source_loop)
+            if source_loop is None or source_loop is events._get_running_loop():
+                source.cancel()
+            else:
+                source_loop.call_soon_threadsafe(source.cancel)
 
     def _call_set_state(source):
         if (destination.cancelled() and

Lib/test/test_asyncio/test_tasks.py

@@ -3680,6 +3680,18 @@ def task_factory(loop, coro):
         (loop, context), kwargs = callback.call_args
         self.assertEqual(context['exception'], exc_context.exception)
 
+    def test_run_coroutine_threadsafe_and_cancel(self):
+        async def target():
+            # self.loop.run_in_executor(None, _in_another_thread)
+            thread_future = asyncio.run_coroutine_threadsafe(self.add(1, 2), self.loop)
+            await asyncio.sleep(0)
+
+            thread_future.cancel()
+            await asyncio.sleep(0)
+
+        self.loop.run_until_complete(target())
+        self.assertEqual(0, len(self.loop._ready))
+
 
 class SleepTests(test_utils.TestCase):
     def setUp(self):