diff --git a/django/contrib/auth/tests/signals.py b/django/contrib/auth/tests/signals.py
index 51f14d35f0..e570280ada 100644
--- a/django/contrib/auth/tests/signals.py
+++ b/django/contrib/auth/tests/signals.py
@@ -1,6 +1,8 @@
-from django.test import TestCase
-from django.test.utils import override_settings
 from django.contrib.auth import signals
+from django.contrib.auth.models import User
+from django.test import TestCase
+from django.test.client import RequestFactory
+from django.test.utils import override_settings
 
 
 @override_settings(USE_TZ=False, PASSWORD_HASHERS=('django.contrib.auth.hashers.SHA1PasswordHasher',))
@@ -47,3 +49,16 @@ class SignalTestCase(TestCase):
         self.client.get('/logout/next_page/')
         self.assertEqual(len(self.logged_out), 1)
         self.assertEqual(self.logged_out[0].username, 'testclient')
+
+    def test_update_last_login(self):
+        """Ensure that only `last_login` is updated in `update_last_login`"""
+        user = User.objects.get(pk=3)
+        old_last_login = user.last_login
+
+        user.username = "This username shouldn't get saved"
+        request = RequestFactory().get('/login')
+        signals.user_logged_in.send(sender=user.__class__, request=request,
+            user=user)
+        user = User.objects.get(pk=3)
+        self.assertEqual(user.username, 'staff')
+        self.assertNotEqual(user.last_login, old_last_login)