Fatal error: Uncaught Error: Class "Drupal\Tests\migrate\Unit\process\MigrateProcessTestCase" not found in /home/www/drupal8/test/core/modules/migrate/tests/src/Unit/process/MigrationTest.php:21 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/migrate/tests/src/Unit/process/MigrationTest.php on line 21