Working Effectively with Legacy Code

Chapter 3: Sensing and Separation

Ideally, we wouldn’t have to do anything special to a class to start working with it. In an ideal system, we’d be able to create objects of any class in a test harness and start working. We’d be able to create objects, write tests for them, and then move on to other things. If it were that easy, there wouldn’t be a need to write about any of this, but unfortunately, it is often hard. Dependencies among classes can make it very difficult to get particular clusters of objects under test. We might want to create an object of one class and ask it questions, but to create it, we need objects of another class, and those objects need objects of another class, and so on. Eventually, you end up with nearly the whole system ...