Part 2. Well-rounded applications
The second part covers when things don’t go as planned. What happens if an application panics? How do you have tests that help catch problems before they occur in production? Chapter 4 focuses on errors and panics—how things can be handled well when they go wrong. This is especially true when handling panics and errors on goroutines. Chapter 5 shifts gears into debugging and testing. This includes logging problems so that you can debug when situations arise in production.