Fatal error: Uncaught Error: Class "Drupal\Tests\migrate_drupal\Kernel\d7\MigrateDrupal7TestBase" not found in /home/www/drupal8/test/core/modules/user/tests/src/Kernel/Migrate/d7/MigrateUserMailTest.php:12 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/user/tests/src/Kernel/Migrate/d7/MigrateUserMailTest.php on line 12