Fatal error: Uncaught Error: Class 'PHPUnit\Framework\TestCase' not found in C:\xampp\htdocs\admin\vendor\luecano\numero-a-letras\tests\NumeroALetrasTest.php:8 Stack trace: #0 {main} thrown in C:\xampp\htdocs\admin\vendor\luecano\numero-a-letras\tests\NumeroALetrasTest.php on line 8