Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in D:\xampp\htdocs\SSWPOS\vendor\guzzlehttp\psr7\tests\DroppingStreamTest.php:11 Stack trace: #0 {main} thrown in D:\xampp\htdocs\SSWPOS\vendor\guzzlehttp\psr7\tests\DroppingStreamTest.php on line 11