Fatal error: Uncaught Error: Class "Drupal\BuildTests\QuickStart\QuickStartTestBase" not found in /home/qcsvlel/www/core/tests/Drupal/BuildTests/Command/GenerateThemeTest.php:23 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/tests/Drupal/BuildTests/Command/GenerateThemeTest.php on line 23