Pragmatic Unit Testing in Java with JUnit, 3rd Edition

Chapter 8Refactoring to Cleaner Code

In Parts I and II, you dug deep into how to write unit tests and take advantage of JUnit. In this part, you’ll learn to take advantage of unit tests to help shape the design of your system, as well as document the numerous unit-level behavioral choices you’ve made. Your ability to keep your system simpler and your tests clearer can reduce your development costs considerably.

You’ll start by focusing on design “in the small,” addressing the lack of clarity and excessive complexity that’s commonplace in most systems. You’ll accomplish this by learning to refactor—making small, frequent edits to the code you write. Your design improvements will help reduce the cost of change.

In a clear, well-designed system, ...