Fatal error: Uncaught Error: Class "Drupal\Core\Cache\CacheCollector" not found in /home/www/drupal8/test/core/tests/Drupal/Tests/Core/Cache/CacheCollectorHelper.php:10 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/tests/Drupal/Tests/Core/Cache/CacheCollectorHelper.php on line 10