Writing Testable Symfony Apps

Do you struggle as soon as you want to test a controller or a repository? Do you feel like it's sometimes impossible to write unit tests for a Symfony application? In this talk, I will show you design patterns that will not only make testing your Symfony applications trivial, but will also make your code a pleasure to work with.

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1. Writing Testable Symfony Apps SYMFONY WORLD ONLINE | JUN, 2022 @afilina
2. “Our tests are slow.“ “We can’t really write unit tests.” “Tests are hard to maintain.”
3. Anna Filina • Coding since 1997 • PHP since 2003 • Legacy archaeology • Test automation • Public speaking • Mentorship • YouTube videos
4. class MyController extends AbstractController { public function index(): Response { return $this->render('my/index.html.twig', [ 'variable' => 'value', ]); } }
5. class MyControllerTest extends TestCase { public function testIndex(): void { $controller = new MyController(); $controller->index(); } }
6. Error : Call to a member function has() on null ./vendor/symfony/framework-bundle/Controller/AbstractController.php:254 ./vendor/symfony/framework-bundle/Controller/AbstractController.php:266 ./src/Controller/MyController.php:14 ./tests/Controller/MyControllerTest.php:25
7. class MyController extends AbstractController { public function index(): Response { return $this->render('my/index.html.twig', [ 'variable' => 'value', ]); } }
8. use Twig\Environment; class MyTestableController { public function __construct(private Environment $twig) { } public function index(): Response { $html = $this->twig->render('my/index.html.twig', [ 'var' => 'value', ]); return new Response($html); } }
9. services: App\Controller\: resource: '../src/Controller/' tags: ['controller.service_arguments']
10. public function testIndex(): void { $controller = new MyTestableController( $twig = $this->createMock(Environment::class) ); $twig ->method('render') ->with('my/index.html.twig', ['var' => 'value']) ->willReturn('some content'); self::assertEquals( 'some content', $controller->index()->getContent() ); }
11. Time: 00:00.089, Memory: 10.00 MB OK (1 test, 1 assertion)
12. Unit Integration MyController Address AddressRepository routes.php
13. Unit Integration MyController Address AddressRepository routes.php
14. Unit Integration MyController Address AddressRepository routes.php
15. Unit Integration MyController Address AddressRepository routes.php
16. MyController Address AddressRepository GET /saved-addresses routes.php
17. # Behat feature file Scenario: Buyer can purchase using a credit card Given I selected a product When I submit a valid credit card Then I should see a payment receipt afilina.com/learn
18. • Routes • Service container • Security • Cache, Twig and other packages
19. UI MyController Address AddressRepository routes.php
20. UI MyController Address AddressRepository routes.php
21. UI MyController Address AddressRepository routes.php
22. AddressRepository Access database Map records to classes
23. if ($address->isBilling() && $address->getCountry() !== 'Canada') { //... }
26. Doctrine Entities
30. SubscriptionRenewal Mocked PaymentProvider
31. SubscriptionRenewal Mocked PaymentProvider
32. SubscriptionRenewal Real PaymentProvider
33. SubscriptionRenewal Real PaymentProvider
34. cardToken amount description ChargeRequest
35. final class ChargeRequest { public function __construct( readonly public string $token, readonly public int $amount, readonly public string $description ) {} }
36. SubscriptionRenewal PaymentProvider
37. SubscriptionRenewal PaymentProvider
38. final class ChargeRequest { public function __construct( readonly public string $token, readonly public int $amount, readonly public string $description ) { if ($amount < 0) { throw new \DomainException('Amount cannot be lower than 0'); } } }
39. Isn’t that overkill for an edge case?
40. • Avoid extending framework classes • Use multiple test types in tandem (pyramid) • Extract business logic from infrastructure • Use small immutable classes
41. @afilina Questions?