Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home2/yiikharazmisabt/public_html/yii2-app/vendor/sebastian/diff/tests/DiffTest.php:20 Stack trace: #0 {main} thrown in /home2/yiikharazmisabt/public_html/yii2-app/vendor/sebastian/diff/tests/DiffTest.php on line 20