Maciej Polańczyk - Mock it right! A beginner’s guide to world of tests and mocks.
Channel: EuroPython Conference
Date: 2017-09-28

"Mock it right! A beginner’s guide to world of tests and mocks.
[EuroPython 2017 - Talk - 2017-07-10 - Arengo]
[Rimini, Italy]

The main goal of this presentation is to make beginner audience familiar with mocks and patches but there is a chance that more experienced ones will also find something new for themselves. Presentation shows the common use cases when developing unit tests. I will say what are the best practices when working with mocks and patches and what kind of mistakes, done by many developers, may be avoided so the dragons will not come. During this presentation I will prepare mock-it-o drink as a prize.

First, I will briefly introduce an audience with the topic of unit testing. Then I will show a simple code which will be tested during the presentation. It covers all common use cases of writing unit tests which are usage of mocks, patches and their side effects. In the end I will show a template of unit test which will be extended according to our needs.

Next, I will say what is a mock, and what are the benefits of using it. Why it is better than any Dummy class implemented for purpose of unit tests and, what is the most important and sometimes forgotten by experienced developers, how to create the best mock, which involves using spec_set and spec to protect us from dragons when interface of mocked class changes.

Last but not least part of my presentation will be dedicated to patches. I will explain when and how patches should be used (how to use side_effect, patch properties and environment variables). Finally, I will say how to avoid common mistakes when working with patches.

License: This video is licensed under the CC BY-NC-SA 3.0 license: https://creativecommons.org/licenses/by-nc-sa/3.0/
Please see our speaker release agreement for details: https://ep2017.europython.eu/en/speaker-release-agreement/