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