The Minitest Cookbook

Written by Chris Kottom
Learning to test your Ruby and Rails code can be tough. Even after you’ve been through blog posts and tutorials, screencasts and demo apps, you might find yourself feeling more lost than ever.

  • Fighting bad and missing docs to get your testing stack set up
  • Learning an entirely new syntax before you can write your first test
  • Hoping no one notices the parts of your application that aren’t tested because you weren’t sure how to do it
  • Watching your test runs get slower and slower over time
Ruby and Rails developers emphasize testing for good reasons, and you want to get on board, but even so, it can be damn hard to learn. You just want to write tests that tell you when you’re breaking something, run fast, and guide you in your work.

If you want to use even the most simple tool effectively, you need to know how to hold it. That’s why I’m writing The Minitest Cookbook - to help Ruby and Rails developers at all skill levels master the techniques they need to write clear, maintainable tests and help others to do the same. That process begins with a set of fundamentals where you’ll learn how to:

  • Write tests using both assertions and specs
  • Structure your tests for clarity and confidence
  • Validate your code with assertions and expectations
  • Use mocks, stubs, and other kinds of test doubles
  • Effectively manage test data
  • Share common code between tests
  • Run one test case or your whole suite
Once you’ve covered the basics and your feel you’re ready to move to the next level, we’ve got you covered, and so does Minitest. Because even though it’s compact, Minitest is also super flexible and ready to test whatever sort of Ruby code you want to throw at it. It’s based around a simple architecture and supports customizations via plugins, so you’ll be able to trick out your testing stack with third-party gems from a large and growing ecosystem of plugins. Later sections of the book will deal with advanced topics on a deeper level including how to:

  • Test your Rails 5 applications from top to bottom
  • Customize your test reports with better, more actionable information
  • Cover hard-to-reach code that you couldn’t test before
  • Write custom assertions and expectations specifically for your application
  • Build and release your own framework extensions