For teaching and continuity reasons, this book does rush through a few of the topics related to creating games for iOS, although it does give you a starting point for almost everything you need to do if you want to create your own game.
Testing is a big part of creating video games. Generally, games see many iterations of bug fixes and changes before submitting or even after submitting the game to the Apple Store. To aid this process, Apple does have a service called test flight. You can use this service by first navigating to your iTunes Connect account and then navigating to Users and Roles. Here, you can set up the Test Flight users who can then download the TestFlight app, so they will be alerted and will be able to test the game that you are creating.
You can even hire QA groups to play and test your game. Alternatively, you can use many forums to ask people to test. Feedback is a huge part of creating a quality product. It is highly advised that you find an avenue to...