Fatal error: Uncaught Error: Class 'PHPUnit_Extensions_Database_TestCase' not found in /home/mpolsk5/public_html/visibilityfuel.com/vendor/creocoder/yii2-nested-sets/tests/DatabaseTestCase.php:15 Stack trace: #0 {main} thrown in /home/mpolsk5/public_html/visibilityfuel.com/vendor/creocoder/yii2-nested-sets/tests/DatabaseTestCase.php on line 15