  from django.core import management
  from django.core.cache import (cache, caches, CacheKeyWarning,
      InvalidCacheBackendError, DEFAULT_CACHE_ALIAS)
  from django.core.context_processors import csrf
  from django.db import connection, connections, router, transaction
  from django.core.cache.utils import make_template_fragment_key
  from django.http import HttpResponse, StreamingHttpResponse
  from django.middleware.cache import (FetchFromCacheMiddleware,
      UpdateCacheMiddleware, CacheMiddleware)
  from django.middleware.csrf import CsrfViewMiddleware
 
</s> remove from django.db import connections, models, router
from django.test import TestCase
from django.test.utils import captured_stdout, override_settings
 </s> add from django.db import connections, models
from django.test import TestCase, override_settings
from django.test.utils import captured_stdout </s> remove from django.db import connections, DEFAULT_DB_ALIAS, router
from django.test import TestCase
 </s> add from django.db import connections, DEFAULT_DB_ALIAS
from django.test import TestCase, override_settings </s> remove from django.test import override_settings
from django.db import connection, migrations, models, router
 </s> add from django.db import connection, migrations, models </s> remove from django.db import connection, router
 </s> add from django.db import connection </s> remove from django.test import TestCase, skipUnlessDBFeature
 </s> add from django.test import TestCase, override_settings, skipUnlessDBFeature
from django.db import connection, connections, transaction
  from django.core import management
  from django.core.cache import (cache, caches, CacheKeyWarning,
      InvalidCacheBackendError, DEFAULT_CACHE_ALIAS)
  from django.core.context_processors import csrf
from django.db import connection, connections, transaction
  from django.core.cache.utils import make_template_fragment_key
  from django.http import HttpResponse, StreamingHttpResponse
  from django.middleware.cache import (FetchFromCacheMiddleware,
      UpdateCacheMiddleware, CacheMiddleware)
  from django.middleware.csrf import CsrfViewMiddleware
keep keep keep keep replace keep keep keep keep keep
 Replaced router.routers usage with override_settings(DATABASE_ROUTERS); refs #23933. 
tests/cache/tests.py