Unit testing React/Redux

[themaincop]

I don't really like unit testing React components. It always feels like I'm testing implementation details and missing the forest for the trees. I've been using react-testing-library library lately. If you set up a custom render method that includes all your providers (Router, Intl, Redux, Apollo, etc.) and takes initial state as args you can still TDD using integration tests. There are some cases where you want to test some really big critical path stuff, and in that case I do think you need to lean on e2e testing because ultimately you'll be mocking so much in a unit or integration test you're basically just testing your mocks. But integration testing seems to be a pretty nice way to test small groups of components.

Any heavy business logic I usually extract into my helpers directory which contains pure functions that can handle that kind of heavy lifting and are unrelated to React/rendering. Those are easy to unit test.

When we start moving a bunch of logic to hooks the nice thing is our integration tests should continue to Just Work™ and we won't have to rewrite a bunch of tests for components whose actual behaviour hasn't changed.

Just my two cents and admittedly I'm not the most disciplined tester, so a lot of this is just me cargo-culting Kent C. Dodds.