In this chapter, we will learn how to configure applications using simple, robust tools based on environment variables. We'll learn about configurability and its importance to testability. We'll deal with real-world configuration concerns that come up during development and testing. We'll address these concerns in a way that makes testing easy but addresses the safety and security requirements of a production environment.
Although we won't directly use RSpec at all in this chapter, its contents are the most important in this book. That is because proper configuration management is fundamental to testability and is something that is often done wrong. You can learn about RSpec easily from other sources, but configurability is one of those real-world concerns that is difficult to learn except the hard way: though direct experience, making mistakes, and learning from them through trial and error.
Here is what we will cover in this chapter:
Configuration via environment...