diff --git a/django/contrib/sessions/tests.py b/django/contrib/sessions/tests.py
index 24d7ac7367..f39d46a8f6 100644
--- a/django/contrib/sessions/tests.py
+++ b/django/contrib/sessions/tests.py
@@ -513,7 +513,7 @@ class CacheSessionTests(SessionTestsMixin, unittest.TestCase):
         self.assertNotEqual(caches['sessions'].get(self.session.cache_key), None)
 
 
-class SessionMiddlewareTests(unittest.TestCase):
+class SessionMiddlewareTests(TestCase):
 
     @override_settings(SESSION_COOKIE_SECURE=True)
     def test_secure_session_cookie(self):
@@ -605,7 +605,8 @@ class SessionMiddlewareTests(unittest.TestCase):
         )
 
 
-class CookieSessionTests(SessionTestsMixin, TestCase):
+# Don't need DB flushing for these tests, so can use unittest.TestCase as base class
+class CookieSessionTests(SessionTestsMixin, unittest.TestCase):
 
     backend = CookieSession