waitFor + getByRole causing severe delays

• @testing-library/dom version: 7.26.6
• node version: 14.3.0

Relevant code or config:

it("Causes a big delay", async () => {
      // This fires a fetch request that is mocked using MSW (so it should be near instant)
      userEvent.click(screen.getByRole("button", { name: "Search"}));

      await waitFor(() => {
        //super fast call
        //screen.getByText("some_link_text");

        // causes massive delays
        screen.getByRole("link", { name: "some_link" });
      });
    });

What you did:

Running this test causes the fetch request promise to resolve a lot longer than usual (around 1.5 - 2s). I initially investigated this by wrapping console.time around the request.

I also had an additional test which looks very similar to the above, but instead of using getByRole it was using getByText to search for some text. That test took a fraction of the time:

What happened:

After changing getByRole to getByText or inserting a getByText query before the getByRole it resolved much faster. My working theory is that getByRole is so expensive that it was monopolising the waitFor loop and takes a long time to relinquish control to the pending promise that needs to resolve.

[herecydev]

The problem is when the knowledge has been propogated differently;

https://kentcdodds.com/blog/common-mistakes-with-react-testing-library#using-the-wrong-query https://testing-library.com/docs/guide-which-query/#priority

There’s absolutely nothing in the docs about the downsides of ByRole, and previously I’ve been happy to accept the small performance hit for the better testing methodology. But this issue is straight out problematic now.

I would love to get an action on how best proceed with this, do we:

1. auto-increment waitFor intelligently
2. Change inner workings of ByRole to be asynchronous
3. Provide documentation around this known issue with suitable guidance

etc.

[radfahrer]

I just ran into this and found that switching from findByRole with name: to findByText saved me over a second per test. I understand that *byRole is more specific, and thus more reliable for getting the correct element. However, as far as “confidence” goes, I’m going to advise my team to avoid findByRole. The reason I found this performance issue is because I’m working on fixing a flaky test suite. The delay introduced by findByRole is causing our test suite to time out intermittently and therefore reduces confidence in our tests.

I would highly recommend improving the performance of *byRole if possible.