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waitFor not working when vi.useFakeTimers is used #565
Description
When vi.useFakeTimers is used in a test, waitFor does not longer run change detection.
it('works', async () => {
vi.useFakeTimers()
const view = await render(MyComponent)
view.detectChanges()
expect(screen.getByRole('input').toHaveAccessibleDescription(/something/))
})
it('does not work', async () => {
vi.useFakeTimers()
await render(MyComponent)
await waitFor(() => expect(screen.getByRole('input').toHaveAccessibleDescription(/something/)))
})It only happens when using Vitest, not when using Jest. (in fact, globalThis.jest = vi in the setup script suffices as workaround for some reason)
The cause appears to be the use of setTimeout in the waitForWrapper: https://github.com/testing-library/angular-testing-library/blob/main/projects/testing-library/src/lib/testing-library.ts#L592
The problem disappears when I replace
setTimeout(() => detectChanges(), 0);with
Promise.resolve().then(() => detectChanges());I assume that waitFor itself is using the fake setTimeout and thus never runs, waiting for the time to advance.
Activity
ThiloAschebrock commentedon Mar 4, 2026
A workaround is to configure the fake timers to advance time via
vi.userFakeTimers({ shouldAdvanceTime: true }).timdeschryver commentedon Mar 8, 2026
@jonaskuske could you see any problems if we change the timeout to your suggested implementation? If not, I think it's a good suggestion, and you can create a PR with this change.
This should also be resolved in #570.
fix: replace setTimeout with queueMicrotask to prevent deadlock
jonaskuske commentedon Mar 11, 2026
I don't think so, PR is out :)
(no guarantee though,
Promise.resolve()/queueMicrotask()will make this a microtask rather than a task, so the timing can be a bit different)fix: replace setTimeout with queueMicrotask to prevent Vitest deadlock (
github-actions commentedon Mar 11, 2026
🎉 This issue has been resolved in version 19.1.1 🎉
The release is available on:
Your semantic-release bot 📦🚀