Fatal error: Uncaught Error: Class "Symfony\Component\HttpKernel\Kernel" not found in C:\xampp\htdocs\electronica\vendor\sensio\framework-extra-bundle\Tests\Fixtures\TestKernel.php:20 Stack trace: #0 {main} thrown in C:\xampp\htdocs\electronica\vendor\sensio\framework-extra-bundle\Tests\Fixtures\TestKernel.php on line 20