Better-than-nothing testing for Django
Your new Django site need tests. Nothing super fancy, just enough that you know you’ve not forgotten to close some <div> somewhere and it’s not going to start 500ing next time you deploy. You could write unit tests, but those are boring and your client sure as hell isn’t going to pay for the time.
You’ve got five minutes, though.
- Iterates through a list of URLs and complains if any of them 500.
- Will loudly complain when there are views missing from the list of URLs to test.
- Has what you need
- Comes with optional mixins for checking links and validating HTML, JSON, your spelling, or WCAG compliance.
- Easily add tests that will run against every view on your website. If you want tests for things like consistent capitalisation of a particular phrase or the universal inclusion of a particular meta tag, you can have them in minutes.
- Tested on Python 2.7, 3.4, 3.5, and 3.6 with Django versions 1.4 to 2.0, with some exclusions.
Changes made in each release are listed in tags in this repository.
pip install django-instant-coverage
‘Write’ your tests
You’ll want a tests module somewhere. I keep mine in my PROJECT_DIR, because it’s testing the whole site and not just one app. Wherever you put it, it should be named such that your test runner will find it (tests.py usually works well) and should contain at least the following:
from django.test import TestCase from instant_coverage import InstantCoverageMixin class EverythingTest(InstantCoverageMixin, TestCase): pass
With that in place, you should be able to run your tests with python manage.py test. They’ll fail, though. You’ll get a list of URLs you’ve not told it to test, looking something like this:
AssertionError: The following views are untested: ('^',) ^$ (index) ('^admin/',) ^$ (index) ('^admin/',) ^logout/$ (logout) ('^admin/',) ^password_change/$ (password_change) [...]
It’ll probably contain a bunch of URLs you don’t want to test, though, like those from the Django admin app. To quickly exclude entire URL includes, add tuples like the ones shown in the failure you just got to your test’s uncovered_includes attribute:
class EverythingTest(InstantCoverageMixin, TestCase): uncovered_includes = [ ('^admin/',), ]
Add paths matching the URLs that you do actually want to test to covered_urls, and add paths that match those you don’t to uncovered_urls. If you forget what’s still missing, run the tests again to get an audit of what’s left.
class EverythingTest(InstantCoverageMixin, TestCase): covered_urls = [ '/', '/api/', '/0007C3F2760E0541/', ] uncovered_urls = [ # requires stuff to be in the session '/upload/confirm/', '/shortlist-selection/', # only accepts POST '/shortlist-order/', # probably tested pretty thoroughly by the django project '/media/woof.jpg', ]
If you want to use reverse() rather than hard-code URLs or if you want to test more than one path for a given URL, that is fully supported. Encouraged, even. It doesn’t matter how you build it, as long as covered_urls is a list.
Use the provided optional test mixins
By default, Instant Coverage will make sure none of your views raise unhandled exceptions and all of them return status codes between 200 and 399. There’s a good chance at least some of the provided optional mixins will be appropriate for your website, so be sure to have a look through them and see what strikes your fancy. Use them like this:
from instant_coverage import InstantCoverageMixin, optional class EverythingTest( optional.Spelling, optional.ExternalLinks, optional.ValidHTML5, InstantCoverageMixin, TestCase ): # covered_urls, etc...
Write your own tests
InstantCoverageMixin provides an instant_responses method that returns a dictionary of Django test client Response objects keyed by URL. Test methods you write should iterate across that. Have a look at the optional mixins for some examples.
If you make any that you think might be useful to any other websites, even if a minority, a pull request would be very much appreciated.
Test under different circumstances
If you want to test all the URLs you’ve listed under different circumstances (for instance, when a user is logged in or when a different language has been selected), create a subclass of your tests and override setUp(). For instance, you might put the following below your EverythingTest:
from django.contrib.auth import get_user_model class LoggedInEverythingTest(EverythingTest): def setUp(self): super(LoggedInEverythingTest, self).setUp() user = get_user_model()( username='user', is_staff=True, is_superuser=True, ) user.set_password('pass') user.save() self.assertTrue(self.client.login(username='user', password='pass'))
Be aware that, by default, the test client will follow redirects. If you do not want this, set the follow_redirects attribute of your tests to False. If you have more specific requirements, you may have to override the get_client_kwargs or attempt_to_get_internal_url methods of your test.
If you have a bunch of test classes that test the same collection of URLs, you may want to consider inheriting from InstantCoverageAPI instead of InstantCoverageMixin; the former will not run any tests that you don’t explicitly add yourself.