Symfony Integration test for route configuration: controller does neither exist as service nor as class

RouterTest.php

<?php

namespace Tests\Integration;

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface;
use Symfony\Component\HttpKernel\HttpKernelInterface;
use Symfony\Component\Routing\RouterInterface;

/**
 * Integration test for Symfony. Validate that all routes are configured with a valid controller.
 * 
 * @author Jérôme Tamarelle (@GromNaN)
 */
class RouterTest extends KernelTestCase
{
    public function testRouteControllerExist()
    {
        self::bootKernel();

        /** @var RouterInterface $router */
        $router = self::$kernel->getContainer()->get('router');
        $controllerResolver = $this->getControllerResolver(self::$kernel->getContainer()->get('http_kernel'));

        $errors = [];
        foreach ($router->getRouteCollection()->all() as $name => $route) {
            $request = new Request();
            $request->attributes->set('_controller', $controller = $route->getDefault('_controller'));

            try {
                $controllerResolver->getController($request);
            } catch (\InvalidArgumentException $exception) {
                $errors[$name] = $controller;
            }
        }

        $this->assertSame([], $errors, 'Some controller does neither exist as service nor as class.');
    }

    private function getControllerResolver(HttpKernelInterface $httpKernel): ControllerResolverInterface
    {
        $reflection = new \ReflectionClass($httpKernel);
        $property = $reflection->getProperty('resolver');
        $property->setAccessible(true);

        return $property->getValue($httpKernel);
    }
}

Thanks for sharing this! I'm just adding it 😉

I see you're using reflection to get controller resolver.
I checked our tests and there we get ControllerResolver directly like this:

$this->controllerResolver = self::$container->get('debug.controller_resolver');