Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\soli\vendor\spomky-labs\base64url\tests\Base64UrlTest.php:20 Stack trace: #0 {main} thrown in C:\xampp\htdocs\soli\vendor\spomky-labs\base64url\tests\Base64UrlTest.php on line 20