Fatal error: Uncaught Error: Class "Drupal\Tests\taxonomy\Functional\TaxonomyTestBase" not found in /home/qcsvlel/www/core/modules/taxonomy/tests/src/Functional/RssTest.php:15 Stack trace: #0 {main} thrown in /home/qcsvlel/www/core/modules/taxonomy/tests/src/Functional/RssTest.php on line 15