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