Proper way to test a Symfony2 Service with Doctrine - symfony

Question

I'm struggling to find the correct way to unit test my symfony 2 services which use doctrine or other common services.
What i have done so far:
In my understanding the controller actions should:
be as short as possible
take the request
execute required methods from injected services
build a response out of this
is a service itself
To accomplish a lightweight action, i try to encapsule the logic into a separate service which gets injected into the controller.
This works nicely expect for testing everything.
Here my current code:
Controller
class SearchController
{
// search_helper, request and templating are controller-injected
protected $search_helper;
protected $request;
protected $templating;
// ...
public function searchAction()
{
$searchterm = strtolower($this->request->query->get('q'));
$result = $this->search_helper->findSamples($searchterm);
// Found a single result. Redirect to this page
if (is_string($result))
{
return new RedirectResponse($result, 301);
}
return new Response($this->templating->render('AlbiSampleBundle:Search:index.html.twig', array('results' => $result)));
}
}
SearchService
class SearchHelper
{
// doctrine, session and min_query_len are controller-injected
protected $doctrine;
protected $session;
protected $min_query_len;
// ...
public function findSamples($searchterm)
{
if (strlen($searchterm) < $this->min_query_len)
{
$msg = 'Your search must contain at least 3 characters!';
$this->session->getFlashBag()->add('error', $msg);
return false;
}
$em = $this->doctrine->getManager();
$results = $em->getRepository('AlbiSampleBundle:Sample')->findPossibleSamples($searchterm);
// Execute a more advanced search, if std. search don't delivers a result
// ...
return $results;
}
}
How can i test this code correctly?
The repository is tested with phpunit_db and a inmemory sqlite database ✓
The action can be tested through a simple functional test ✓
What's left is the logic in the search-service. e.g. the findSamples method
My first thought was to mock the dependencies (in fact that was one of the main aspects in separating the dependencies), but you not only have to mock the doctrine object, but also the entitymanager and the repository.
$em = $this->doctrine->getManager();
$results = $em->getRepository('AlbiSampleBundle:Sample')->findPossibleSamples($searchterm);
I think there must be a better solution. Not only would this mocking need many LOCs, it also doesn't feel right. The test would be unnecessarily coupled really tight to the SUT.
EDIT
Here is a sample test i came up with. Using mock objects.
The test won't work. I realized it would take much more mock-objects and i got the feeling this isn't the right way.
The test fails because SessionMock->getFlashbag doesn't return a flashbag with add method.
doctrine->getManager returns no EntityManager. The EntityManager has no getRepository method. And the repository is missing findPossibleSamples.
class SearchHelperTest extends \PHPUnit_Framework_TestCase
{
private $router;
private $session;
private $doctrine;
public function setUp()
{
parent::setUp();
// ...
}
public function testSearchReturnValue()
{
$search_service = $this->createSearchHelper();
$this->assertFalse($search_service->findSamples('s'));
}
protected function createSearchHelper()
{
return new SearchHelper($this->doctrine, $this->router, $this->session, 3);
}
protected function getDoctrineMock()
{
return $this->getMock('Doctrine\Bundle\DoctrineBundle\Registry', array('getManager'), array(), '', false);
}
protected function getSessionMock()
{
return $this->getMock('Symfony\Component\HttpFoundation\Session\Session', array('getFlashBag'), array(), '', false);
}
protected function getRouterMock()
{
return $this->getMock('Symfony\Component\Routing\Router', array('generate'), array(), '', false);
}
}
Hope the community can help me, writing well tested code :)
cheers

Answer 1

For your specific example I would argue that the validation of the $searchterm doesn't really belong in your service - at the very least a service should never depend on the session. There are ways you could move the session out of the service and leave the validation in but personally I would use symfony validation for this i.e. have a SampleSearchType for the form that uses itself as the data class and hang the validation off that in validation.yml (or using annotations as appropriate).
Once that validation is taken out, what's left from your question is another findX() method to be added to the repository (there's no reason why repository methods can't call and build on each other) which you already know how to test.
Having said that, I still agree that with Symfony there is a general issue of how to test services in isolation from injected services. With respect to testing in isolation from the persistence layer I've avoiding trying to do this so far. My business layer services are so tightly coupled with the persistence layer that the cost of trying to test them independently is not worthwhile (what logic there is consists mainly of making related db updates or sending emails for which symfony provides it's own decoupling mechanism). I'm not sure if this is because I'm doing it wrong or because the apps I'm working on are light on business logic!
To isolate service tests from dependencies other than persistence I've tried:
Overriding service classes with mocked versions in the configuration. Issue - you don't want to do this for functional tests which means you have to have tests scripts which update the configuration and/or change the config to run individual tests. Advantage - you can run the same test as an isolated unit test and as an integration test by flipping the config
(Warning: nasty hack!) providing a setter method to replace an injected service with a mocked version from the test program.
(Not yet tried) Directly instantiate the service being tested, passing mock dependencies in on construction.
With respect to isolating from the persistence layer the only approach that makes sense to me is to abstract it out of the service to be tested into a wrapper service which contains no additional logic. The wrapper service could then be mocked using one of the above approaches (or hopefully a better solution that someone else is going to suggest?!)
EDIT: to address the issue of complexity of mocking dependencies - very occasionally this may be unavoidable but in general this is an indication that the design needs revisiting. This is one of the strengths of TDD - it strongly encourages simplified design and decoupling of components:
No service should need to be dependent upon the session object. This is not good practice and can always be avoided. Worst case the example method could return mixed values and if the result is not an array it's assumed to be an error message, although there are better alternatives.
Sometimes dependencies are unnecessary (code more naturally belongs elsewhere) or too general (I would question the necessity of injecting high level objects like doctrine or e.g. the container into anything other than test helpers).
If there is a complex dependency to mock (such as on multiple classes from the persistence layer) abstract it out into a wrapper which is far simpler to mock than the complex dependency.