Fatal error: Uncaught Error: Class "Drupal\Tests\views\Functional\ViewTestBase" not found in /home/www/drupal8/test/core/modules/views/tests/src/Functional/Handler/ArgumentStringTest.php:13 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/views/tests/src/Functional/Handler/ArgumentStringTest.php on line 13