In this chapter, you learned how Xcode can help you write tests to make sure that your code is running as expected. We covered the ideas behind Test-driven development and how to follow them in practice.

You also learned about functional unit tests, how to write them, and how they help you test portions of your code. Then you learned about UI testing and how you can simulate and reproduce user actions in a controlled manner to test your views. Finally, you learned how to run, view, and see how much of your code is covered by tests.

In the next chapter, you'll learn how to load your apps onto your own devices, how to optimize large apps for distribution, and how to submit them to the App Store.