Add Django email testing support

[lorin]

This commit adds support for inspecting emails sent that were sent by the Django server.

I would appreciate some help in getting my tests integrated into the existing test framework. Currently the tests are in lettuce/django/tests/functional.

You can manually verify this code works by going into the lettuce/django/tests/functional' directory and doingmake test`. There's a test_email.py there that is supposed to do the same thing, but nose is failing because of a Django-related issue.

[gabrielfalcao]

Hello @lorin,
I love your commits, lettuce rarely gets people contributing with so much test coverage, I just love it.

I'd just like to understand why not just use Django's locmem email backend.

I usually use that for testing emails being sent from django apps:

settings/testing.py

EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'

then inside a test:

from sure import expect
from django.core import mail

def test_email_was_sent():
    expect(mail).to.have.property("mail").being.empty

    my_model = MyModel.objects.get(name="foobar")
    my_model.send_email()

    expect(mail.outbox).to.have.length_of(1)

[gabrielfalcao]

Also we can't make lettuce just change the setting EMAIL_BACKEND like it's being done here

For example at yipit we use the locmem backend for testing, so let's say I apply this pull request and make a new release; our tests would start to fail because lettuce is replacing the setting without asking for permission
👊

[lorin]

Hi @gabrielfalcao

The locmem backend works great for unit tests, but I could not get it to work properly when using Django with Lettuce.

As I understand it, the problem is that the Django server runs in a different process than the code that's running inside of steps.py, since the Django server is started by multiprocessing. Since locmem keeps things in memory instead of the database, the code executing in steps.py has a different copy of mail.outbox than the code executing inside of the Django server, since they are in separate memory address spaces.

I agree that we don't want to break existing tests, and if it's working with your lettuce tests, than that means I'm wrong about the behavior of locmem here.

Let me try to write a failing test that uses locmem as a backend to illustrate the problem. In the meantime, do you have any open source code from yipit or elsewhere that uses Lettuce, Django and locmem that I could take a look at?

[danclaudiupop]

harvest.py is using django.test.utils.setup_test_environment that overrides email backend to locmem whether you specify a different EMAIL_BACKEND in settings.

As @lorin said django server runs in a different process than lettuce and therefore you are not able to access mail.outbox.

[gabrielfalcao]

ok guys, that's awesome