2 files changed, 19 insertions, 2 deletions
diff --git a/Lib/test/test_unittest/test_async_case.py b/Lib/test/test_unittest/test_async_case.py
index a465103..ba1ab83 100644
--- a/Lib/test/test_unittest/test_async_case.py
+++ b/Lib/test/test_unittest/test_async_case.py
@@ -484,5 +484,19 @@ class TestAsyncCase(unittest.TestCase):
         result = test.run()
         self.assertTrue(result.wasSuccessful())
 
+    def test_loop_factory(self):
+        asyncio.set_event_loop_policy(None)
+
+        class TestCase1(unittest.IsolatedAsyncioTestCase):
+            loop_factory = asyncio.EventLoop
+
+            async def test_demo1(self):
+                pass
+
+        test = TestCase1('test_demo1')
+        result = test.run()
+        self.assertTrue(result.wasSuccessful())
+        self.assertIsNone(support.maybe_get_event_loop_policy())
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/unittest/async_case.py b/Lib/unittest/async_case.py
index bd2a471..63ff6a5 100644
--- a/Lib/unittest/async_case.py
+++ b/Lib/unittest/async_case.py
@@ -25,12 +25,15 @@ class IsolatedAsyncioTestCase(TestCase):
     # them inside the same task.
 
     # Note: the test case modifies event loop policy if the policy was not instantiated
-    # yet.
+    # yet, unless loop_factory=asyncio.EventLoop is set.
     # asyncio.get_event_loop_policy() creates a default policy on demand but never
     # returns None
     # I believe this is not an issue in user level tests but python itself for testing
     # should reset a policy in every test module
     # by calling asyncio.set_event_loop_policy(None) in tearDownModule()
+    # or set loop_factory=asyncio.EventLoop
+
+    loop_factory = None
 
     def __init__(self, methodName='runTest'):
         super().__init__(methodName)
@@ -118,7 +121,7 @@ class IsolatedAsyncioTestCase(TestCase):
 
     def _setupAsyncioRunner(self):
         assert self._asyncioRunner is None, 'asyncio runner is already initialized'
-        runner = asyncio.Runner(debug=True)
+        runner = asyncio.Runner(debug=True, loop_factory=self.loop_factory)
         self._asyncioRunner = runner
 
     def _tearDownAsyncioRunner(self):