Testing the untestable: a beginner’s guide to mock objects

Mock objects can be a powerful tool to write easy, reliable tests for the most difficult to test code. In this session you will learn your way around Python 3’s unittest.mock package starting at the simplest examples and working through progressively more problematic code. You’ll learn about the Mock class, sentinels and patching and how and when to use each of them. You will see the benefits that mocks can bring and learn to avoid the pitfalls. Along the way I’ll fill you in on some of the bewildering terminology surrounding mocks such as “SUT”, “Stub”, “Double”, “Dummy” , “mockist” and more and I’ll give a brief plug for my own mockextras package that can enhance your mock experience.