Designing and writing tests aren't the most exciting things in the world, we know, but tests are absolutely essential for any app you write. They might be the difference between a shining 5-star app on the AppStore, or a bug-ridden collection of code. We all know what Unit Tests are and how to write them, but since XCode 7, Apple has introduced us to UI tests inside their IDE. With these tests, you can record a user's interactions with your app and check to see whether it's behaving as it should.