Fatal error: Uncaught Error: Class "tests\DatabaseTestCase" not found in /var/www/html/prod/vendor/creocoder/yii2-nested-sets/tests/NestedSetsQueryBehaviorTest.php:19 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/creocoder/yii2-nested-sets/tests/NestedSetsQueryBehaviorTest.php on line 19