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