Development with Python

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1 if = 1 More Test
A rule of thumb for these sorts of tests: any if means an extra test, and any try/
except means an extra test, so this should be about four tests. Let’s start with one:
accounts/tests/test_authentication.py.
from unittest.mock import patch
from django.test import TestCase
from accounts.authentication import (
PERSONA_VERIFY_URL, DOMAIN, PersonaAuthenticationBackend
)
class AuthenticateTest(TestCase):
@patch('accounts.authentication.requests.post')
def test_sends_assertion_to_mozilla_with_domain(self, mock_post):
backend = PersonaAuthenticationBackend()
backend.authenticate ('an assertion')
mock_post.assert_called_once_with (
PERSONA_VERIFY_URL,
data={'assertion': 'an assertion' , 'audience': DOMAIN}
)
In authenticate.py we’ll just have a few placeholders:
accounts/authentication.py.
import requests
PERSONA_VERIFY_URL =
DOMAIN = 'localhost'
class PersonaAuthenticationBackend(object ):
def authenticate (self, assertion):
pass
At this point we’ll need to:
(virtualenv)$ pip install requests
Don’t forget to add requests to requirements.txt too, or the next
deploy won’t work…
Then let’s see how the tests get on!
$ python3 manage.py test accounts
[...]
AssertionError: Expected 'post' to be called once. Called 0 times.
286 | Chapter 16: Server-Side Authentication and Mocking in Python