Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in C:\xampp\htdocs\vendor\athlon1600\php-curl-file-downloader\tests\DownloadTest.php:9 Stack trace: #0 {main} thrown in C:\xampp\htdocs\vendor\athlon1600\php-curl-file-downloader\tests\DownloadTest.php on line 9