Unable to get mock container to return anything but null - symfony

Question

I have a test that fails due to me being unable to successfully stub the get method of the Controller:
1) Tests\my-project\BackendBundle\Service\PdfGenerateServiceTest::test_getHttpPathToPtImage_should_return_the_default_avatar_when_photo_is_null
TypeError: Argument 1 passed to Mock_Pdf_d0288d34::setLogger() must implement interface Psr\Log\LoggerInterface, null given, called in /var/www/my-project/src/my-project/BackendBundle/Service/PdfGenerateService.php on line 66
The test
public function test_getHttpPathToPtImage_should_return_the_default_avatar_when_photo_is_null()
{
$protocolAndHost = "http://foo.bar.com";
$service = new PdfGenerateService($this->createFileServiceMock(), $this->createTranslatorMock(), $this->createSnappyMock(), $this->createContainerMock(), $protocolAndHost);
$httpPathToPtImage = $service->getHttpPathToPtImage(null);
self::assertEquals($httpPathToPtImage, $protocolAndHost . "abc/def");
}
The constructor that is failing
public function __construct(FileService $fileService, Translator $translator, Pdf $snappy, ContainerInterface $container, string $protocolAndHost)
{
$this->fileService = $fileService;
$this->translator = $translator;
$this->currentLocale = $this->translator->getLocale();
/* Could reconfigure the service using `service.yml` to pass these in using DI */
$this->twig = $container->get('twig');
$this->logger = $container->get('logger'); // <--- should not be null
$timeoutInSeconds = 15; // can be high, since the job is done async in a job (user does not wait)
$snappy->setLogger($this->logger); // <--- THIS FAILS due to $this->logger being null
The stubs
protected function createContainerMock()
{
$containerMock = $this->createMock('Symfony\Component\DependencyInjection\ContainerInterface');
$loggerMock = $this->createLoggerMock();
$containerMock->method('get')->will($this->returnValueMap([
['logger', $loggerMock]
]));
return $containerMock;
}
I do not really understand why the the get('logger') call just returns null when I have setup a mock to be returned using the returnValueMap call above.
By chance, I just found a SO question on this topic where someone mentioned that you need to supply all parameters, even optional ones. I then checked out the interface, which does indeed list a second parameter:
public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE);
Still, changing the map to ['logger', null, $loggerMock] made no change, so I am a bit at a loss as to what to try next.
Phpunit 6.5, PHP 7.2, Symfony 3.4

Answer 1

You were really close to the solution. When providing a value for an optional parameter in returnValueMap, you must use the value itself, not just null.
So instead of
['logger', null, $loggerMock]
try specifying
['logger', ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE, $loggerMock]
Complete call looks like this:
$containerMock->method('get')->will($this->returnValueMap([
['logger', ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE, $loggerMock]
]));