AppKernel.php

<?php

use Symfony\Component\ClassLoader\DebugUniversalClassLoader;
use Symfony\Component\Config\Loader\LoaderInterface;
use Symfony\Component\HttpKernel\Debug\ErrorHandler;
use Symfony\Component\HttpKernel\Debug\ExceptionHandler;
use Symfony\Component\HttpKernel\Kernel;

class AppKernel extends Kernel
{
    static protected $databaseConnection;
    static protected $rabbitmqConnection;

    // bla bla register bundles 

    public function boot()
    {
        parent::boot();

        if ('test' === $this->getEnvironment()) {
            if (null === static::$databaseConnection) {
                static::$databaseConnection = $this->getContainer()->get('doctrine.dbal.default_connection');
            } else {
                $this->getContainer()->set('doctrine.dbal.default_connection', static::$databaseConnection);
            }

            if (null === static::$rabbitmqConnection) {
                static::$rabbitmqConnection = $this->getContainer()->get('old_sound_rabbit_mq.connection.default');
            } else {
                $this->getContainer()->set('old_sound_rabbit_mq.connection.default', static::$rabbitmqConnection);
            }
        }
    }
}