Add

AppBundle.php

<?php

use Symfony\Component\Config\Resource\FileResource;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\HttpKernel\Bundle\Bundle;

class AppBundle extends Bundle
{
    public function build(ContainerBuilder $container)
    {
        // Add `test.php` as a resource to the container.
        // Any changes to the file `test.php` will trigger the container cache to be rebuilt
        // Note: This only works when Symfony is in development mode
        $container->addResource(new FileResource(dirname(__DIR__).'/test.php'));
    }
}