React native lib testing, how to await the onsubmit fetch

[wcastand]

https://github.com/wcastand/react-hook-form-test

when i run the test, the test fails because it has no time to go to next screen in the onSubmit.

In my real app, i get a mutation/fetch too and same result, the toHavePathname doesn't work but first transition works.

not sure how i'm suppose to make it work. any help appreciated.
i tried act or to waitFor but doesn't do anything

[KrishnaSaxena108]

Hi @wcastand !!

What’s happening is that handleSubmit in react-hook-form can be async, and so can your navigation (router state updates aren’t synchronous). In a test, if you immediately assert after fireEvent.submit or userEvent.click, the transition hasn’t completed yet.

A couple of ways to fix it:

1. Make sure your submit handler returns a promise
2. Await the effect in your test

If you’re using next/navigation, the push happens in a microtask → so waitFor is required. act() won’t help unless you wrap the async.

So the pattern is: trigger submit → await waitFor until router has updated. That should make your toHavePathname assertion reliable.

[wcastand]

i'm on expo/ expo-router not next so not sure how it's working exactly.
also since then testing/native lib got update to support Suspense.
I just didn't have much time to look into it more because we have other issues with tests.

But i will try again later on thanks for the explanation

[KrishnaSaxena108]

Got it — makes sense, Expo Router will have its own timing quirks compared to Next. Glad the context helped though. Feel free to circle back once you’ve had a chance to try again, and good luck with the other test issues!