params.md

Testing using Parametrization

After each of these steps please feel free to commit your changes, run your tests, and push them to Github!

$ <Make changes to tests.>
$ python setup.py test
$ git commit -a
$ git push origin master
$ <Check your pull request for Travis build results!>

1. Try enhancing your tests in tests/test_catmath.py to make use of pytest.mark.parametrize.

   @pytest.mark.parametrize('age', [
       ...
   ])
   def test_cat_to_hooman(age):
       ...

2. Try enhancing your tests in tests/test_safecatmath.py to also use pytest.mark.parametrize.

3. Take a look at the McCattery class in catinabox/mccattery.py. Doesn't it look an awful lot like the Cattery?

   In this step you will attempt (and succeed!) in making the tests in tests/test_cattery.py run against both the Cattery and McCattery. This step assumes that you have completed the previous activity where you refactored the cattery tests to use a fixture.

   @pytest.fixture
   def cattery_client():
       return cattery.Cattery()
   
   def test_the_things(cattery_client):
       ...

   First we start by parametrizing the fixture.

   @pytest.fixture(params=[
       ...
   ])
   def cattery_client(request):
       ...

   Don't worry about the magical request argument for now. It can do a lot of things, but we'll be using its ability to access that params argument we passed to pytest.fixture.

   Everytime pytest goes to create this fixture, it will assign the next thing in params to request.param. As you hopefully heard from the slides, pytest will run every possible permutation of fixtures and the tests that require them.

   Think of all the testing possibilities!