HelloController.php

<?php
namespace Application\HelloBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

/** @Service(id="hello_controller") */
class HelloController extends Controller
{
    protected $userRepository;
    protected $logger;
    protected $auth;

    /** @Inject({logger="logger", auth="my_auth_service_id"}) */
    public function __contruct(Logger $logger, Auth $auth)
    {
        $this->logger = $logger;
        $this->auth = $auth;
    }

    /** @Inject("user_repository") */
    public function setUserRepository($userRepository)
    {
        $this->userRepository = $userRepository;
        return $this;
    }

    public function indexAction($name)
    {
        $user = $this->userRepository->findOneByName($name);
        return $this->render('HelloBundle:Hello:index', array('user' => $user));
    }
}

test.php

<?php

$controller = new Controller(new NullLogger(), $this->getMockAuthService());
$controller->setUserRepository($this->getMockUserRepository());

//assert something

UserRepository.php

<?php
namespace Application\HelloBundle\Repository;

use Doctrine\ORM\EntityRepository;

/** @Service(id="user_repository") */
class UserRepository extends EntityRepository
{
    protected $logger;

    /** @Inject("zend.logger") */
    public function setLogger($logger)
    {
        $this->logger = $logger;
        return $this;
    }

    public function createUser($user)
    {
        $this->_em->persist($user);
        $this->logger->info('User ' . $user->getName() . ' successfully persisted.');
    }
}

Well, you're right, but only if you don't test controllers.
Read, the justification in the first message here http://groups.google.com/group/symfony-devs/browse_thread/thread/7766abae81097e9d