Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in C:\xampp\htdocs\ApiSigestWin\1.0\vendor\symfony\mime\Tests\CharacterStreamTest.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ApiSigestWin\1.0\vendor\symfony\mime\Tests\CharacterStreamTest.php on line 17