Python 3 Object-Oriented Programming - Third Edition

Organizing and running tests

It doesn't take long for a collection of unit tests to grow very large and unwieldy. It can quickly become complicated to load and run all the tests at once. This is a primary goal of unit testing: trivially run all tests on our program and get a quick yes or no answer to the question, did my recent changes break anything?.

As with normal program code, we should divide our test classes into modules and packages that keep them organized. If you name each test module starting with the four characters test, there's an easy way to find and run them all. Python's discover module looks for any modules in the current folder or subfolders with names that start with test. If it finds any TestCase objects in these modules, ...