'Look up the activation key for the user, then hit the activate view.
No error checking.'

def activate_user(self, email):

    activation_key = Registration.objects.get(user__email=email).activation_key
    url = reverse('activate', kwargs={'key': activation_key})
    self.assert_account_activated(url)
    user = User.objects.get(email=email)
    self.assertTrue(user.is_active)
    return user
