In this chapter, we will examine several often overlooked, but valuable, aspects of programming, chiefly testing, user experience, and dependency graphs. While these topics might not feel like they have anything to do with; Dependency Injection (DI), they have been included to give you a solid but pragmatic foundation from which you can evaluate the techniques in the second part of this book.

The following topics will be covered in this chapter:

• Optimizing for humans
• A security blanket named unit tests
• Test-induced damage
• Visualizing your package dependencies with Godepgraph