Laravel 13.31: checking that an email is sent only once

assertSentOnce() and assertSentOnDemandOnce(): the Mail and Notification fakes finally say “exactly once” in one word.

New in Laravel 13.31. Mail::assertSent() passes as soon as an email has been sent, whether there was one or ten. To require a single send, you needed assertSentTimes(…, 1). The Mail and Notification fakes now have …Once assertions.

Before

Mail::assertSentTimes(CommandeConfirmee::class, 1);
Notification::assertSentOnDemandTimes(CommandeAFacturer::class, 1);

Since Laravel 13.31

Mail::assertSentOnce(CommandeConfirmee::class);
Notification::assertSentOnDemandOnce(CommandeAFacturer::class);

There is also assertQueuedOnce() for queued emails, and assertSentToOnce($notifiable, …) for a notification sent to a model.

Your task

POST /api/orders sends a confirmation to the customer (CommandeConfirmee) and notifies accounting (CommandeAFacturer). The test in tests/Feature/CommandeTest.php checks that both are sent, but not that they are sent only once: a duplicate send would go unnoticed. Strengthen it with the …Once assertions. Each mutant (a duplicated send) must make your tests fail.

Checking that an email is sent only once

Before

Since Laravel 13.31

Your task