Working Effectively with Legacy Code

Chapter 12: I Need to Make Many Changes in One Area. Do I Have to Break Dependencies for All the Classes Involved?

In some cases, it’s easy to start writing tests for a class. But in legacy code, it’s often difficult. Dependencies can be hard to break. When you’ve made a commitment to get classes into test harnesses to make work easier, one of the most infuriating things that you can encounter is a closely scattered change. You need to add a new feature to a system, and you find that you have to modify three or four closely related classes. Each of them would take a couple of hours to get under test. Sure, you know that the code will be better for it at the end, but do you really have to break all of those dependencies individually? Maybe not. ...