it works now

Author: kumaraditya303

Lib/asyncio/tasks.py

@@ -1055,8 +1055,10 @@ def _leave_task(loop, task):
             raise RuntimeError(f"Leaving task {task!r} does not match "
                             f"the current task {loop._current_task!r}.")
     except AttributeError:
-        pass
-    loop._current_task = None
+        raise RuntimeError(f"Leaving task {task!r} does not match "
+                        f"the current task.")
+    else:
+        loop._current_task = None
 
 
 def _swap_current_task(loop, task):

Lib/test/test_asyncio/test_tasks.py

@@ -3002,7 +3002,9 @@ def done(self):
 
     def test__enter_task(self):
         task = mock.Mock()
-        loop = mock.Mock()
+        class LoopLike:
+            pass
+        loop = LoopLike()
         self.assertIsNone(asyncio.current_task(loop))
         self._enter_task(loop, task)
         self.assertIs(asyncio.current_task(loop), task)
@@ -3011,7 +3013,9 @@ def test__enter_task(self):
     def test__enter_task_failure(self):
         task1 = mock.Mock()
         task2 = mock.Mock()
-        loop = mock.Mock()
+        class LoopLike:
+            pass
+        loop = LoopLike()
         self._enter_task(loop, task1)
         with self.assertRaises(RuntimeError):
             self._enter_task(loop, task2)
@@ -3021,14 +3025,20 @@ def test__enter_task_failure(self):
     def test__leave_task(self):
         task = mock.Mock()
         loop = mock.Mock()
+        class LoopLike:
+            pass
+        loop = LoopLike()
         self._enter_task(loop, task)
         self._leave_task(loop, task)
         self.assertIsNone(asyncio.current_task(loop))
 
     def test__leave_task_failure1(self):
         task1 = mock.Mock()
         task2 = mock.Mock()
-        loop = mock.Mock()
+
+        class LoopLike:
+            pass
+        loop = LoopLike()
         self._enter_task(loop, task1)
         with self.assertRaises(RuntimeError):
             self._leave_task(loop, task2)
@@ -3037,7 +3047,10 @@ def test__leave_task_failure1(self):
 
     def test__leave_task_failure2(self):
         task = mock.Mock()
-        loop = mock.Mock()
+
+        class LoopLike:
+            pass
+        loop = LoopLike()
         with self.assertRaises(RuntimeError):
             self._leave_task(loop, task)
         self.assertIsNone(asyncio.current_task(loop))