Testing React

RelativeCI - In-depth bundle stats analysis and monitoring - Interview with Viorel Cojocaru

In order to encourage people to support my work, I've decided to publish a TL;DR version of this chapter for the community. This will allow me to develop more content, so it's a win-win really.

You can access the full chapter by buying a copy through Leanpub. It goes into detail, whereas the following should give you a rough idea of the chapter contents.


  • Basic testing techniques include unit testing, acceptance testing, property based testing, and mutation testing.
  • Unit testing allows us to ascertain specific certain truths.
  • Acceptance testing allows us to test qualitative aspects of our system.
  • Property based testing (see QuickCheck) is more generic and allows us to cover a wider range of values more easily. These tests are more difficult to write, though.
  • Mutation testing makes it possible to test the tests. Unfortunately, it's not a particularly popular technique with JavaScript yet.
  • Cesar Andreu's web-app has a nice testing setup (Mocha/Karma/Istanbul).
  • Code coverage helps us to understand what parts of the code remain untested. It does not, however, give us any guarantees of the quality of our tests.
  • React Test Utilities give us a nice way to write unit tests for components. There are lighter APIs, such as jquense/react-testutil-query.
  • Alt provides a good means for testing actions and stores.
  • Testing provides you confidence. This will become particularly important as your codebase grows. It will become harder to break things inadvertently.

Buy the book for more detail.

Previous chapter
Advanced Techniques
Next chapter
Typing with React

This book is available through Leanpub. By purchasing the book you support the development of further content.

Need help?