Fatal error: Uncaught Error: Class "Drupal\Core\Config\ConfigBase" not found in /home/www/drupal8/test/core/lib/Drupal/Core/Config/StorableConfigBase.php:25 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/lib/Drupal/Core/Config/StorableConfigBase.php on line 25