Testing email sending in Django
PythonDjangoEmailSmtpDjango TestingPython Problem Overview
I need to test that my Django application sends e-mails with correct content. I don't want to rely on external systems (like an ad-hoc gmail account), since I'm not testing the actual e-mail service...
I would like to, maybe, store the emails locally, within a folder as they are sent. Any tip on how to achieve it?
Python Solutions
Solution 1 - Python
Django test framework has some built in helpers to aid you with testing e-mail service.
Example from docs (short version):
from django.core import mail
from django.test import TestCase
class EmailTest(TestCase):
def test_send_email(self):
mail.send_mail('Subject here', 'Here is the message.',
'[email protected]', ['[email protected]'],
fail_silently=False)
self.assertEqual(len(mail.outbox), 1)
self.assertEqual(mail.outbox[0].subject, 'Subject here')
Solution 2 - Python
You can use a file backend for sending emails which is a very handy solution for development and testing; emails are not sent but stored in a folder you can specify!
Solution 3 - Python
If you are into unit-testing the best solution is to use the In-memory backend provided by django.
EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'
Take the case of use it as a py.test fixture
@pytest.fixture(autouse=True)
def email_backend_setup(self, settings):
settings.EMAIL_BACKEND = 'django.core.mail.backends.locmem.EmailBackend'
In each test, the mail.outbox
is reset with the server, so there are no side effects between tests.
from django.core import mail
def test_send(self):
mail.send_mail('subject', 'body.', '[email protected]', ['[email protected]'])
assert len(mail.outbox) == 1
def test_send_again(self):
mail.send_mail('subject', 'body.', '[email protected]', ['[email protected]'])
assert len(mail.outbox) == 1
Solution 4 - Python
Use MailHog
> Inspired by MailCatcher, easier to install. > > Built with Go - MailHog runs without installation on multiple platforms.
Also, it has a component called Jim, the MailHog Chaos Monkey, which enables you to test sending emails with various problems happening:
> What can Jim do? > > * Reject connections > * Rate limit connections > * Reject authentication > * Reject senders > * Reject recipients
Read more about it here.
(Unlike original mailcatcher, which failed on me when sending emails with emoji, encoded in UTF-8 and it WASN'T really fixed in the current release, MailHog just works.)
Solution 5 - Python
For any project that doesn't require sending attachments, I use django-mailer, which has the benefit of all outbound emails ending up in a queue until I trigger their sending, and even after they've been sent, they are then logged - all of which is visible in the Admin, making it easy to quickly check what you emailing code is trying to fire off into the intertubes.
Solution 6 - Python
Django also has an in-memory email backend. More details in the docs under In-memory backend. This is present in Django 1.6 not sure if it's present in anything earlier.
Solution 7 - Python
Patching SMTPLib for testing purposes can help test sending mails without sending them.
Solution 8 - Python
Why not start your own really simple SMTP Server by inherit from smtpd.SMTPServer
and threading.Thread
:
class TestingSMTPServer(smtpd.SMTPServer, threading.Thread):
def __init__(self, port=25):
smtpd.SMTPServer.__init__(
self,
('localhost', port),
('localhost', port),
decode_data=False
)
threading.Thread.__init__(self)
def process_message(self, peer, mailfrom, rcpttos, data, **kwargs):
self.received_peer = peer
self.received_mailfrom = mailfrom
self.received_rcpttos = rcpttos
self.received_data = data
def run(self):
asyncore.loop()
process_message is called whenever your SMTP Server receive a mail request, you can do whatever you want there.
In the testing code, do something like this:
smtp_server = TestingSMTPServer()
smtp_server.start()
do_thing_that_would_send_a_mail()
smtp_server.close()
self.assertIn(b'hello', smtp_server.received_data)
Just remember to close()
the asyncore.dispatcher
by calling smtp_server.close()
to end the asyncore loop(stop the server from listening).
Solution 9 - Python
Tying a few of the pieces here together, here's a straightforward setup based on filebased.EmailBackend
. This renders a list view linking to the individual log files, which have conveniently timestamped filenames. Clicking a link in the list displays that message in the browser (raw):
Settings
EMAIL_BACKEND = "django.core.mail.backends.filebased.EmailBackend"
EMAIL_FILE_PATH = f"{MEDIA_ROOT}/email_out"
View
import os
from django.conf import settings
from django.shortcuts import render
def mailcheck(request):
path = f"{settings.MEDIA_ROOT}/email_out"
mail_list = os.listdir(path)
return render(request, "mailcheck.html", context={"mail_list": mail_list})
Template
{% if mail_list %}
<ul>
{% for msg in mail_list %}
<li>
<a href="{{ MEDIA_URL }}email_out/{{msg}}">{{ msg }}</a>
</li>
{% endfor %}
</ul>
{% else %}
No messages found.
{% endif %}
urls
path("mailcheck/", view=mailcheck, name="mailcheck"),
Solution 10 - Python
If you have a TomCat server available, or other servlet engine, then a nice approach is "Post Hoc" which is a small server that looks to the application exactly like a SMTP server, but it includes a user interface that allows you to view and inspect the email messages that were sent. It is open source and freely available.
Find it at: Post Hoc GitHub Site
See the blog post: PostHoc: Testing Apps that Send Email