Fatal error: Uncaught Error: Class "Symfony\Component\HttpKernel\Kernel" not found in C:\xampp\htdocs\electronica\vendor\symfony\assetic-bundle\Tests\TestKernel.php:18 Stack trace: #0 {main} thrown in C:\xampp\htdocs\electronica\vendor\symfony\assetic-bundle\Tests\TestKernel.php on line 18