diff -u b/core/tests/Drupal/Tests/Core/Cache/DatabaseBackendFactoryTest.php b/core/tests/Drupal/Tests/Core/Cache/DatabaseBackendFactoryTest.php
--- b/core/tests/Drupal/Tests/Core/Cache/DatabaseBackendFactoryTest.php
+++ b/core/tests/Drupal/Tests/Core/Cache/DatabaseBackendFactoryTest.php
@@ -7,10 +7,8 @@
 use Drupal\Core\Cache\DatabaseBackend;
 use Drupal\Core\Cache\DatabaseBackendFactory;
 use Drupal\Core\Database\Connection;
-use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\Site\Settings;
 use Drupal\Tests\UnitTestCase;
-use Symfony\Component\DependencyInjection\Definition;
 
 /**
  * @coversDefaultClass \Drupal\Core\Cache\DatabaseBackendFactory