We said before that unit tests help us write better code, because the moment we want to start testing parts of the code, we usually have to write them to be testable, which often means they are also cohesive, granular, and small. These are all good traits to have in a software component.
Another interesting gain is that testing will help us notice code smells in parts where we thought our code was correct. One of the main warnings that our code has code smells is whether we find ourselves trying to monkey-patch (or mock) a lot of different things just to cover a simple test case.
The unittest module provides a tool for patching our objects at unittest.mock.patch. Patching means that the original code ...
