diff --git a/django/contrib/auth/tests/__init__.py b/django/contrib/auth/tests/__init__.py
index b3007ea484b..038c8980d9d 100644
--- a/django/contrib/auth/tests/__init__.py
+++ b/django/contrib/auth/tests/__init__.py
@@ -14,3 +14,16 @@ from django.contrib.auth.tests.tokens import *
 from django.contrib.auth.tests.views import *
 
 # The password for the fixture data users is 'password'
+
+from django.dispatch import receiver
+from django.test.signals import setting_changed
+
+
+@receiver(setting_changed)
+def user_model_swapped(**kwargs):
+    if kwargs['setting'] == 'AUTH_USER_MODEL':
+        from django.db.models.manager import ensure_default_manager
+        from django.contrib.auth.models import User
+        # Reset User manager
+        setattr(User, 'objects', User._default_manager)
+        ensure_default_manager(User)
diff --git a/django/contrib/auth/tests/basic.py b/django/contrib/auth/tests/basic.py
index bc7344f753e..2c807cca517 100644
--- a/django/contrib/auth/tests/basic.py
+++ b/django/contrib/auth/tests/basic.py
@@ -162,6 +162,8 @@ class BasicTestCase(TestCase):
     def test_swappable_user(self):
         "The current user model can be swapped out for another"
         self.assertEqual(get_user_model(), CustomUser)
+        with self.assertRaises(AttributeError):
+            User.objects.all()
 
     @override_settings(AUTH_USER_MODEL='badsetting')
     def test_swappable_user_bad_setting(self):