Automated testing of your web application is a very important thing, do it from day one! Aim for fast tests that aren't annoying to wait for -- this encourages continous integration.
We initially wrote BDD Tests to test the server, as it sounded to be a very nice way to describe the behavior of the software. But it didn't work out so well for us: we ended up having tests that took over half an hour to run through and tested the whole stack, i.e. the web server, external libraries and multiple times the same parts of our code.
Not only are Unit Tests super fast (by testing isolated parts of your code), they also force you to better structure the code to make it testable.
Install nose and the Django test runner django-nose (installation instructions).
Fasten-up the tests by reusing the database:
REUSE_DB=1 ./manage.py test
TODO: Avoid the DB. Explain https://factoryboy.readthedocs.org/en/latest/orms.html#django and http://www.voidspace.org.uk/python/mock/
Very often, a test requires data to deal with (some users with profiles, entries etc.). A test function must be self-sufficient (they may be runned in any order), so always create the required objects at the beginning of the function. You can create objects used by multiple test functions in the test case's setUp() function.
To create test objects conveniently, we ended up writing a model creation mixin for the most common models of our application. This mixin provides helper functions that, if no arguments are given, create a model that has meaningful default values and randomized unique data (like the username). Here is an example usage of the creation mixin:
class SomeTestCase(TestCase, ModelCreationMixin):
def testSomething():
# create a user with profile using
# default values and a random username
user1 = self.new_user()
# create a user with profile using a specific username
user2 = self.new_user(username='joe')
# test something with user1 and user2
We run JavaScript tests with the Karma test runner from the Grunt task grunt test. Setup Karma by adding the NPM package grunt-karma to your client's dependencies.
The automated client tests should run without a browser UI, so install PhantomJS, the headless WebKit browser, by adding the dependency phantomjs. Then configure Karma to use it:
browsers = ['PhantomJS'];
To load and use templates in tests, precompile them by adding the dependency karma-ng-html2js-preprocessor and define html2js as preprocessor:
preprocessors = {
'app/**/templates/*.html': 'html2js'
};
In tests, templates can then be loaded like this:
beforeEach(module('app/mymodule/templates/mytemplate.html'));
For all the details, checkout the Karma configuration file and the Grunt task from the Braindump application.
Measuring code coverage can be useful, it helps you cover cases you haven't thought about. But don't go for that 100% coverage only to have 100% coverage.
We use coverage.py for Python and Istanbul for JavaScript.
tbd. (configuration details, run)