Fatal error: Uncaught Error: Class 'PHPUnit_Extensions_Database_TestCase' not found in /var/www/html/autocar/vendor/creocoder/yii2-nested-sets/tests/DatabaseTestCase.php:15 Stack trace: #0 {main} thrown in /var/www/html/autocar/vendor/creocoder/yii2-nested-sets/tests/DatabaseTestCase.php on line 15