Congratulations! You've made it to the end of this lengthy, information-packed chapter. You should know enough about testing and accessibility right now to begin exploring testing in greater depth than we have in this chapter. No matter how small or big your app, writing automated tests will ensure that your app is of a high quality. More importantly, instead of assuming that something works because it worked before, your automated tests will guarantee that it works because your tests don't pass if you broke your code.

You also learned that writing testable code sometimes requires you to refactor large portions of code. More often than not, these refactoring sessions leave your code in a much better state than before. Code that is easy to test is often cleaner and more robust than code that is hard to test. Now that you know how to cover your app with tests, in the next chapter, we'll look at how you can measure your app's performance using some of the great tools that Xcode provides.