My Symfony functional testing toolbox

Who am I?

Slow test suites

If a build / test suite takes more than 10 minutes to run, it's worthless.

The testing pyramid

...and what was going wrong

My pyramid foundation

Static code analysis

https://phpstan.org

https://psalm.dev

Speed up your tests

Parallelization & isolation

When you ran multiple tests on the same DB at the same time, you run intro troubles...

• facile-it/paraunit-testcase (deprecated)
• dama/doctrine-test-bundle

Kernel caching

facile-it/paraunit-testcase was built on top of something else...

• liip/functional-test-bundle (forked)

  class MyTest extends WebTestCase
  {
      public function test(): void
      {
          $this->getContainer()->get('...');
      }
  }

• facile-it/symfony-functional-testcase

Good fixtures hygiene

DB vendor is part of your system

• It's not worth it to change DB vendor only for tests

Validation of entities

• I used strong validation before persistence
  in multiple projects
• Strict validation ensures that data is good
  once it reaches the DB

Good fixtures lead to good tests

• Fixtures should resemble real data
  AKA don't put invalid data in your entities
• Build *FixtureBuilder utility classes to create fixtures in known valid states
• Randomized fixtures are good
  (use Faker or something else, since it got retired...)

Fixture belong outside of src/

• Fixtures are testing tools, not production code
• maglnet/composer-require-checker
  will report them as failures

Using the tools

No reload, no cleanup required

public function testDeleteFoo(): void
{
    // ...
    $client->request('DELETE', '/api/foo/123');

    $this->assertNull($fooRepo->find(123));
    // no cleanup or fixture reload required!
}

public function testPutFoo(): void
{
    // ...
    $client->request('PUT', '/api/foo/123', $payload);
    // ...
}
                

Getting services from the container

/**
 * @template T of object
 * @param class-string<T> $serviceId
 *
 * @return T
 */
protected function getService(string $serviceId): object
{
    $service = $this->getContainer()->get($serviceId);
    $this->assertInstanceOf($serviceId, $service);

    return $service;
}

Testing a service directly

public function testFindLatestReturnsOnlyOneResult(): void
{
    $repository = $this->getService(FooRepository::class);

    $result = $repository->findLatest();

    $this->assertCount(1, $result);
    $this->assertContainsOnlyInstancesOf(Foo::class, $result);
}

Testing entity validation (1/2)

protected function assertIsValid(object $entity): void
{
    $validator = $this->getContainer()->get('validator');
    $result = $validator->validate($entity);

    $this->assertCount(0, $result, 'Validation failed: ' . $result);
}
                    
protected function assertValidationFailsAtPath(string $path, object $entity): void
{
    $violationList = $this->getContainer()->get('validator')->validate($entity);
    foreach ($violationList as $violation) {
        if ($violation->getPropertyPath() === $path) {
            $this->increaseAssertionCount();
    
            return;
        }
    }
    $this->fail('No violation found at path ' . $path);
}

Testing entity validation (2/2)

public function testNewFooIsValid(): void
{
    $this->assertIsValid(new Foo('baz'));
}
                    
/** @dataProvider invalidDataProvider */
public function testFooIsInvalid(Foo $foo, string $errorPath): void
{
    $this->assertValidationFailsAtPath($errorPath, $foo);
}
                    
public function testFooIsInvalidWithWrongBar(): void
{
    $foo = new Foo();
    $this->assertIsValid($foo);

    $foo->setBar('invalid');

    $this->assertValidationFailsAtPath('bar', $foo);
}

Pitfalls

Doctrine Test Bundle limitations

• Commands with implicit commits break it (TRUNCATE or any schema change)
• No logs nor after-test DB inspections
  (but invalid queries still crash)
• Last resort: force transaction commit
  

  \DAMA\DoctrineTestBundle\Doctrine\DBAL\StaticDriver::commit()

• Tests can fail due to concurrency & DB locks
  (but Paraunit retries those)

Data providers are a strange place...

• PHPUnit's data providers are executed ahead of time
• Do not interact with the entity manager there

All containers are not the same...

public function test(): void
{
    $client = self::createClient();
                    
    $this->assertNotSame(
        $this->getContainer(), 
        $client->getContainer(),
        "Those are not the services you're looking for..."
    );
}

...so you may want the right one

protected function getService(
    string $serviceId,
    KernelBrowser $client = null
): object 
{
    return $this->getContainer($client)->get($serviceId);
}

protected function getContainer(KernelBrowser $client = null): ContainerInterface
{
    if ($client) {
        $clientContainer = $client->getContainer();

        return $clientContainer->get('test.service_container');
    }

    return parent::getContainer();
}

Thanks!

Please rate my talk on Joind.in:

https://joind.in/talk/19e53

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