Development with Python

CHAPTER 17

Test Fixtures, Logging, and

Server-Side Debugging

Now that we have a functional authentication system, we want to use it to identify users,

and be able to show them all the lists they have created.

To do that, we’re going to have to write FTs that have a logged-in user. Rather than

making each test go through the (time-consuming) Persona dialog, we want to be able

to skip that part.

This is about separation of concerns. Functional tests aren’t like unit tests, in that they

don’t usually have a single assertion. But, conceptually, they should be testing a single

thing. There’s no need for every single FT to test the login/logout mechanisms. If we

can figure out a way to “cheat” and skip that part, we’ll spend less time waiting for

duplicated test paths.

Don’t overdo de-duplication in FTs. One of the benefits of an FT is

that it can catch strange and unpredictable interactions between dif‐

ferent parts of your application.

Skipping the Login Process by Pre-creating a Session

It’s quite common for a user to return to a site and still have a cookie, which means they

are “pre-authenticated”, so this isn’t an unrealistic cheat at all. Here’s how you can set it

up:

functional_tests/test_my_lists.py.

from

django.conf

import

settings

from

django.contrib.auth

import

BACKEND_SESSION_KEY

SESSION_KEY

get_user_model

User

get_user_model

()

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