Fatal error: Uncaught Error: Class "Drupal\Component\Plugin\PluginBase" not found in /home/qcsvlel/www/core/tests/Drupal/Tests/Component/Plugin/StubPluginBase.php:12 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/tests/Drupal/Tests/Component/Plugin/StubPluginBase.php on line 12