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