Testing with pytest

Part of the Python course

Welcome back. Up to now you have run code and checked the output with your eyes. That works for a few lines, but the moment you change anything, you have to re-check everything. Tests do that re-checking for you, every time, in seconds. They catch the small breakages you would have missed, and they let you change code with confidence because you can prove out loud that the old behavior still works.

This lesson uses two files: calculator.py (the code under test) and test_calculator.py (the tests). Your workspace already has test_calculator.py. There is no calculator.py in your lesson folder yet. Create it with this code: press Play on the block and the file is made for you. Pressing Play again does not make a second copy. ...