Fatal error: Uncaught Error: Class 'Drupal\Tests\UnitTestCase' not found in /var/www/html/tmp/contrib/flag/tests/src/Unit/Ajax/ActionLinkFlashCommandTest.php:12 Stack trace: #0 {main} thrown in /var/www/html/tmp/contrib/flag/tests/src/Unit/Ajax/ActionLinkFlashCommandTest.php on line 12