Django custom mail backend not working during unit tests

Backend
1

I have configured a custom email backend in my Django settings like this:

EMAIL_BACKEND = 'mailqueue.backend.DatabaseBackend'

This setup works perfectly in production. When I use from django.core.mail import send_mail, emails get stored in the database queue instead of being sent right away.

However, I’m running into issues during testing. When my test cases trigger views that send emails, the custom backend seems to be ignored:

def test_email_functionality(self):
    # Trigger some action that sends emails
    response = self.client.post('/contact/', data)
    
    # This assertion fails - emails appear in outbox instead of queue
    self.assertEqual(len(mail.outbox), 0)  # Fails: 2 != 0
    
    # Database queue remains empty during tests
    queued_emails = QueuedMessage.objects.all()
    self.assertEqual(queued_emails.count(), 2)  # Fails: 0 != 2

Why does Django seem to bypass my custom email backend during test execution? The standard mail.outbox gets populated instead of using my database backend. I need to test the queueing behavior without modifying third-party packages that use django.core.mail.send_mail.

2

also, make sure any email settings in your test config match prod. sometimes if you have different settings, it can cause issues. just double check the whole setup, and see if there’s any diff in your test and actual settings.

3

I encountered this exact issue before. Django automatically overrides your email backend to use django.core.mail.backends.locmem.EmailBackend during testing, regardless of your settings configuration. This happens because Django wants to prevent actual emails from being sent during test execution. To fix this, you need to explicitly override the email backend in your test case using the @override_settings decorator or by setting it in your test settings file. Try adding @override_settings(EMAIL_BACKEND='mailqueue.backend.DatabaseBackend') above your test method. Alternatively, create a separate test settings file that explicitly sets your custom backend and run tests with that configuration. The locmem backend populating mail.outbox is the default Django testing behavior, so you must force it to use your custom backend.

4

hmm thats weird - are you maybe using any test decorators or settings overrides? sometimes django automatically switches to locmem backend during tests. what does your test settings file look like for email config?