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Description:

djangoemailintegrationtest 0.1.0

This Django package provides a comment designed to perform integration tests
for your email setup after deployment.
THIS IS NOT A REPLACEMENT FOR UNIT TESTING YOUR CODE.
Presumably you already do unit testing of the code that generates emails and use
the appropriate setup to avoid actually sending emails to anyone. Perhaps you
run automated tests in development that do actually contact a server and send
emails but the parameters of the test are most likely significantly different
from the production context. Even if your run your tests in a Docker container
that mimics your production environment, at the very least, the IP of your test
server will be different from the IP used in production.
Ultimately none of the above tests are enough to absolutely guarantee that
once your app runs in production with the production settings your emails are
going to get through without problem. It really depends on how the mail relays
between your server and the final destination are setup. It is really easy to
think your email setup works when in fact it does not. Typically, mail sent to
SERVER_EMAIL and similar addresses is forwarded elsewhere, forwarding can be
broken by SPF or other mechanisms designed to reduce spam. The relay you were
hoping to use may not allow relaying from your specific address, etc.
The only way to be sure that the setup is working from end-to-end is to send
emails from the production machine and using the production settings, and
check that they were received.

Requirements
We support Django from 2.2 onwards and Python from 3.6 onwards.
If want to contribute support for earlier versions of Django or Python, you
should open an issue first so that we can discuss your plans. (Do not suggest
support for Python 2.7, Python 3.x versions that are no longer supported, or
Django versions that are no longer supported: your suggestion will be rejected.)

Management Command
Once this package is installed and added to your Django APPS settings, you get a
new command:
manage.py email_integration_test
There are no options.

Configuration
This package has a custom setting. Here is an example:
EMAIL_INTEGRATION_TEST = {
"IDENTIFIER": "my server",
"DESTINATIONS": ["foo@example.com", "bar@example.com"],
"TIMEOUT": 5 * 60,
"ADDITIONAL_FROM_ADDRESSES": ("foo@myserver.com",),
"MAILBOX": {
"TYPE": "IMAP4_SSL",
"HOST": "example.com",
"PORT": 1111,
"USER": "fnord@example.com",
"PASSWORD": "password1234",
}
All settings specific to this package belong under the
EMAIL_INTEGRATION_TEST setting.
IDENTIFIER (mandatory string): a name you choose to identify your server for
the sake of email tests.
DESTINATIONS (mandatory iterable of strings): the addresses to which to send
emails.
TIMEOUT (optional number, default of 5 * 60 seconds): a number in
seconds. If the test emails do not arrive during this time, the test has failed.
ADDITIONAL_FROM_ADDRESSES (optional iterable of strings, defaults to an
empty iterable): use this setting to specify other addresses to test sending
from in addition to sending from SERVER_EMAIL and
DEFAULT_FROM_EMAIL. (Why this setting? It is possible to configure mail
relays to accept relaying from some addresses but not other addresses. So for
some use-case scenarios, it is useful to have the capability to test from more
than SERVER_EMAIL and DEFAULT_FROM_EMAIL.
MAILBOX (mandatory dictionary): specifies the mailbox to use to check that
the emails were correctly sent. This mailbox must be able to read the emails
sent to at least one of the addresses in DESTINATIONS. It contains the
following options:

TYPE (mandatory string): the type of mailbox. Currently only
"IMAP4_SSL" is supported.
HOST (mandatory string): the host to connect to.
PORT (optional number): the port to use to connect to HOST. If blank,
the default port for TYPE is used.
USER (mandatory string): the user name to use to log in.
PASSWORD (mandatory string): the password for USER.

Your email backend must be configured so that django.core.mail.send_mail
works. How to do this depends on which backend you use.

How it works
When you run email_integration_test, then for each unique email address
address in the tuple made from SERVER_EMAIL, DEFAULT_FROM_EMAIL and
the addresses in ADDITIONAL_FROM_ADDRESSES:

send an email from address to DESTINATIONS with the subject:
Server {IDENTIFIER} is testing sending to {address} at {now} ({uid})
where IDENTIFIER and address are the variables defined above, now
is the time at which we started sending emails and {uid} is a unique
identifier associated with address.

Then the tool polls the mailbox specified in MAILBOX for evidence that the
emails arrived at their destination. They must arrive within TIMEOUT for the
test to be successful.

Pick your mail provider carefully
This is true both in production and for testing this code. Some mail providers
impose restrictions on what they accept.
Example 1: GMail does not allow using authenticated SMTP access to send emails
with a From: address which is different from the address of the account used
for logging into the SMTP server. If you have the account foo@gmail.com and
try to send emails as if they were from foo@example.com, your emails will
go through but they’ll be from foo@gmail.com. The explanation is that they
do this to prevent spam, but the fit between this objective and the means to get
there is extremely loose. Since the SMTP access is authenticated, Google would
have the capability to deal with spammers. They just don’t want that burden so
they prevent the ability to send emails from other addresses. (There’s a way to
get Gmail to allow you to select an email address that you prove you control,
but I’ve got no evidence that this also works for SMTP accesses. Besides this
method requires giving Google your user name and password into another mail
server. I don’t trust Google that much.)
This makes GMail a poor candidate for running the test suite (and probably
production but you may have a scenario where it makes sense to use it in
production).

Contributing
Once you’ve cloned the repo, create a new ./secrets.py with appropriate
values. Running the test suite requires real access to a server providing SMTP
and IMAP 4 interfaces. You must pick a server you have access to.
Tests can be run with:
$ make dev-venv
$ make test