Using React Testing Library's findBy Methods to Test Asynchronous Behavior

You can think of waitFor as a way to delay your test until some arbitrary criteria is met. findBy on the other hand is a much more specific tool. Wait until this query resolves. The docs recommend using this tool for cases where you interact with the UI but need to wait a little bit before the changes show up on the page. Like waitFor it checks immediately and then after 50ms up until a 1000ms timeout, which is totally customizable.

The way we're using it here really isn't that optimal because it's generally going to slower than a getBy query. When I ran some tests the first query took around 70ms while the rest all took around 50ms. It might even have been better to explicitly findBy the first heading and then getBy all of the rest or even findByAll and then compare them that way.

Checkout the About Queries section of the Testing Library docs that covers the differences between getBy, findBy and queryBy. Another section called Async Methods covers all of the details around waitFor and findBy.