41.

A Quick Recap

In this chapter, we've described the following keys to effectively designing software with testability in mind:

• Keeping code in the model, not the view.

• Using static type checking to find errors.

• Using mediators to encapsulate functionality across fault lines.

• Writing methods with small signatures and default arguments.

• Using accessors that do not modify memory state.

• Specifying out-of-program components with interfaces.

• Writing tests first.

In Chapter 5, we'll look at how the application of the scientific method can define, refine, and facilitate your code-debugging efforts. In subsequent chapters, we will assume the context of an XP development method and discuss the most common types of bugs that remain in such an environment.