Rethrow non-HTTP exceptions in the test environment (aka functional tester saver)

config_test.yml

...

services:
    listener.exception_rethrow:
        class: App\EventListener\ExceptionRethrowListener
        tags:
            - { name: kernel.event_listener, event: kernel.exception, method: onKernelException }

RethrowExceptionListener.php

<?php

namespace App\EventListener;

use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;

class ExceptionRethrowListener
{
    public function onKernelException(GetResponseForExceptionEvent $event)
    {
        $exception = $event->getException();

        if ($exception instanceof HttpExceptionInterface) {
            return;
        }

        throw $exception;
    }
}