Fatal error: Uncaught Error: Class "Drupal\Tests\views\Functional\ViewTestBase" not found in /home/www/drupal8/test/core/modules/book/tests/src/Functional/Views/BookRelationshipTest.php:15 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/book/tests/src/Functional/Views/BookRelationshipTest.php on line 15