Fatal error: Uncaught Error: Class 'tests\DatabaseTestCase' not found in /home/luxurytr/public_html/lt8/vendor/creocoder/yii2-nested-sets/tests/NestedSetsQueryBehaviorTest.php:19 Stack trace: #0 {main} thrown in /home/luxurytr/public_html/lt8/vendor/creocoder/yii2-nested-sets/tests/NestedSetsQueryBehaviorTest.php on line 19