assert the child did not finish

Author: deadlovelll

Lib/test/test_asyncio/test_taskgroups.py

@@ -1156,13 +1156,17 @@ async def test_taskgroup_cancel_before_create_task(self):
 
     async def test_taskgroup_cancel_from_child_before_first_suspension(self):
         # gh-155418: an eager task can cancel the group before joining _tasks
+        done = []
+
         async def child(tg):
             tg.cancel()
             await asyncio.sleep(10)
+            done.append(True)
 
         async with asyncio.TaskGroup() as tg:
             task = tg.create_task(child(tg))
         self.assertTrue(task.cancelled())
+        self.assertEqual(done, [])
 
     async def test_taskgroup_cancel_before_exception(self):
         async def raise_exc(parent_tg: asyncio.TaskGroup):