Refactor

During the green step, you write just enough code to make all the tests pass again. As I just mentioned, it doesn't matter what the code looks like in the green step. In the refactor step, you should improve the code. You remove duplication, extract common values, and so on. Do what is needed to make the code as good as possible. The tests help you to not break already implemented features while refactoring.

Don't skip this step. Always try to think how you can improve the code after you have implemented a feature. Doing so helps to keep the code clean and maintainable. This ensures that it is always in good shape.

As you have written only a few lines of code since the last refactor step, the changes needed to make the code clean ...

Get Test-Driven iOS Development with Swift 4 - Third Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.