Resolve "Notification: envoi à des groupes utilisateurs"

.junie/guidelines.md

@@ -185,14 +185,57 @@ When we need to use a DateTime or DateTimeImmutable that need to express "now",
 `Symfony\Component\Clock\ClockInterface`, where possible. This is usually not possible in doctrine entities,
 where injection does not work when restoring an entity from database, but usually possible in services.
 
+In test, we use `\Symfony\Component\Clock\MockClock` which is an implementation of `Symfony\Component\Clock\ClockInterface`
+where we have full and easy control of the date.
+
 ### Testing Information
 
 The project uses PHPUnit for testing. Each bundle has its own test suite, and there's also a global test suite at the root level.
 
+#### Use of mock in tests
+
+##### General mocking
+
 For creating mock, we prefer using prophecy (library phpspec/prophecy).
 
+##### Useful helpers and tips that avoid create a mock
+
+Some notable implementations that are tests helper, and avoid to create a mock:
+
+- `\Psr\Log\NullLogger`, an implementation of `\Psr\Log\LoggerInterface`;
+- `\Symfony\Component\Clock\MockClock`, an implementation of `Symfony\Component\Clock\ClockInterface` (already mentioned above);
+- `\Symfony\Component\HttpClient\MockHttpClient`, an implementation of `\Symfony\Contracts\HttpClient\HttpClientInterface`;
+- When using `\Symfony\Component\Mailer\MailerInterface`, we can create the mock with "InMemoryTransport":
+
+    ```php
+    use Symfony\Component\Mailer\Transport\InMemoryTransport;
+    use \Symfony\Component\Mailer\Mailer;
+
+    $transport = new InMemoryTransport();
+    $mailer = new Mailer($transport);
+
+    // After sending:
+    $messages = $transport->getSent(); // array of SentMessage
+    ```
+- When using `\Symfony\Contracts\EventDispatcher\EventDispatcherInterface`, we can use directly an instance of `\Symfony\Component\EventDispatcher\EventDispatcher`;
+
+##### When we prefer not creating a mock
+
+- When we use Doctrine Entities related to the project, we prefer not to use a mock: we instantiate them directly (unless it requires too much code to write);
+
+##### Mocking final and readonly classes
+
+Classes marked as final can't be mocked. To avoid that, either:
+
+- we remove the `final` keyword from the class;
+- we extract an interface from the final class.
+
+This must be a decision made by a human, not by an AI. Every AI task must abort with an explicit message in that case.
+
 #### Running Tests
 
+The tests are run from the project's root (not from the bundle's root).
+
 ```bash
 # Run all tests
 vendor/bin/phpunit