Fixed #29363 -- Added SimpleTestCase.assertWarnsMessage().

tests/cache/tests.py

@@ -10,7 +10,6 @@ import tempfile
 import threading
 import time
 import unittest
-import warnings
 from unittest import mock
 
 from django.conf import settings
@@ -632,12 +631,8 @@ class BaseCacheTests:
         cache.key_func = func
 
         try:
-            with warnings.catch_warnings(record=True) as w:
-                warnings.simplefilter("always")
+            with self.assertWarnsMessage(CacheKeyWarning, expected_warning):
                 cache.set(key, 'value')
-                self.assertEqual(len(w), 1)
-                self.assertIsInstance(w[0].message, CacheKeyWarning)
-                self.assertEqual(str(w[0].message.args[0]), expected_warning)
         finally:
             cache.key_func = old_func