Build Awesome Command-Line Applications in Ruby 2

Moving On

We only scratched the surface of the art of software testing, but we went through a whirlwind tour of everything you’ll need to get started for testing command-line apps. We saw some real challenges with testing our apps, as well as several techniques to deal with them. By manipulating the environment, setting up test-specific infrastructure, and mocking system calls, we can simulate almost anything that might happen when our app runs.

Toward the end, when we learned about unit testing, we talked briefly about refactoring. Refactoring is difficult without tests, but with a good suite of tests, we can safely change the internal design of our code. We got a taste of that when we extracted our business logic out of bin/todo and put ...