Refs #27741 -- Fixed staticfiles_tests.test_views when run in isolation.

tests/staticfiles_tests/settings.py

@@ -22,4 +22,7 @@ TEST_SETTINGS = {
         'staticfiles_tests.apps.test',
         'staticfiles_tests.apps.no_label',
     ],
+    # In particular, AuthenticationMiddleware can't be used because
+    # contrib.auth isn't in INSTALLED_APPS.
+    'MIDDLEWARE': [],
 }