Testing

In general:

• every feature should have tests testing this feature
• error cases should be tested
• no need to be test-driven as long as the tests are in the commit at the end.

Rule of thought:

• write tests that help you to be sure your feature is fine
• prefer tests to manual tests (especially on non-views)
• write tests so no one can break your feature.

3rd party libraries

It is not necessary to test framework features or features of other third-part libraries. But if you glue together some code of libraries, this should be tested.

Mocking and monkey patching

Mock should be only used as an exception. Most times, you can prevent it by using configuration, dependency injection or good code design.

(example: the whole Django test-suite does not use mock at all)

If you can, prefer the pytest monkeypatch to the mock-library.

Don’t do mock-like tests that check method-calls of mocked objects. This is a sign of bad design. You should test actions and check the desired results. Even when this means creating a file locally or saving things to the database.

Manual tests

The unit tests don’t replace a manual test of the feature!