February 26, 2016 Update: Read to the end for Git repo bonus!
TDD is a series of small steps. It can be difficult to grasp until you see those steps demonstrated.
That’s why I made this screencast. It was sparked by a Stack Overflow question that said, “All the examples of unit testing I read about seem to be extremely simple and trivial.” The question asks how to write unit tests for a piece of sample code that uses NSUserDefaults.