[3.13] pythongh-131645: fix ResourceWarnings in test_asyncio.test_events (python#131646) (python#131661)

pythongh-131645: fix ResourceWarnings in `test_asyncio.test_events` (python#131646)

(cherry picked from commit 71ce4ac)

Author: graingert

Lib/test/test_asyncio/test_events.py

@@ -1,6 +1,7 @@
 """Tests for events.py."""
 
 import concurrent.futures
+import contextlib
 import functools
 import io
 import multiprocessing
@@ -57,9 +58,9 @@ def _test_get_event_loop_new_process__sub_proc():
     async def doit():
         return 'hello'
 
-    loop = asyncio.new_event_loop()
-    asyncio.set_event_loop(loop)
-    return loop.run_until_complete(doit())
+    with contextlib.closing(asyncio.new_event_loop()) as loop:
+        asyncio.set_event_loop(loop)
+        return loop.run_until_complete(doit())
 
 
 class CoroLike:
@@ -2892,13 +2893,13 @@ async def main():
     def test_get_running_loop_already_running(self):
         async def main():
             running_loop = asyncio.get_running_loop()
-            loop = asyncio.new_event_loop()
-            try:
-                loop.run_forever()
-            except RuntimeError:
-                pass
-            else:
-                self.fail("RuntimeError not raised")
+            with contextlib.closing(asyncio.new_event_loop()) as loop:
+                try:
+                    loop.run_forever()
+                except RuntimeError:
+                    pass
+                else:
+                    self.fail("RuntimeError not raised")
 
             self.assertIs(asyncio.get_running_loop(), running_loop)