Python 3 Object-Oriented Programming - Third Edition

Test-driven development

Write tests first is the mantra of test-driven development. Test-driven development takes the untested code is broken code concept one step further and suggests that only unwritten code should be untested. We don't write any code until we have written the tests that will prove it works. The first time we run a test it should fail, since the code hasn't been written. Then, we write the code that ensures the test passes, then write another test for the next segment of code.

Test-driven development is fun; it allows us to build little puzzles to solve. Then, we implement the code to solve those puzzles. Then, we make a more complicated puzzle, and we write code that solves the new puzzle without unsolving the previous ...