Testing EMail sending in Django¶

class TestOnboardingEmails(TestCase):
   MSG1 = 'Congratulations! You have now set your first '
       'assignment'
   MSG2 = 'You have been using product for a week now'

   def setUp(self):
       self.teacher = factories.TeacherFactory.create()
       self.teacher.email = 'test@test.domani.com'
       self.teacher.save()
       self.student = factories.StudentFactory.create()
       self.studentset = factories.StudentSetFactory.create(owner=self.teacher)
       self.studentset.join_student(self.student)
       self.studentset.join_teacher(self.teacher)
       self.quick = factories.QuickFactory.create()

       self.original_backend = settings.EMAIL_BACKEND
       settings.EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'

   def tearDown(self):
       settings.EMAIL_BACKEND = self.original_backend


   def test_new_assignment(self):
       aset = AssignmentSet.create(teacher=self.teacher,
                                   assign_date=datetime.now(),
                                   studentset=self.studentset,
                                   students_list=[self.student],
                                   content_list=[{'obj': self.quick,
                                                  'attempt_max':1}])
       cmd = process_events.Command()
       cmd.handle(no_celery=True, debug=False, name=None, date=None,
                  quiet=False)
       self.assertTrue(len(mail.outbox)==1)
       self.assertTrue(self.MSG1 in
                       mail.outbox[0].message().as_string())
       self.assertTrue(self.MSG2 not in
                       mail.outbox[0].message().as_string())

       after_1_week_plus = datetime.now() + relativedelta(days=8)

       cmd.handle(no_celery=True, debug=False, name=None,
                  date=after_1_week_plus.strftime(DATE_FORMAT),
                  quiet=False)
       self.assertTrue(len(mail.outbox)==2)
       self.assertTrue(self.MSG1 not in
                       mail.outbox[1].message().as_string())
       self.assertTrue(self.MSG2 in
                       mail.outbox[1].message().as_string())


if __name__ == '__main__':
   unittest.main()

The important lines in setUp and tearDown:

 def setUp(self):
     self.original_backend = settings.EMAIL_BACKEND
     settings.EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'

 def tearDown(self):
     settings.EMAIL_BACKEND = self.original_backend