Incorrest state when testing with renderHook

[kostrse]

I was trying to test behavior of the useAsync hook using the renderHook from the testing-library/react-hooks, and found the following issues (which is probably I'm trying to use the library in a wrong way).

First, when hook returns it's initial state, it returns initialValue (as expected), but it also indicates that the promise has been already resolved:

it('should set into proper initial state', async () => {
    const asyncFunc = () => Promise.resolve(2);

    const { result } = renderHook(() => useAsync(asyncFunc, { initialValue: 1 }));

    expect(result.current.value).toEqual(1);
    expect(result.current.isResolved).toBe(false); // FAILS, ALREADY RESOLVED
});

I expected it to be either { data: 1, isResolved: false }, or { data: 2, isResolved: true }.

Second issue, is that for some reason the waitForNextUpdate never resolve:

it('should resolve resolved promise', async () => {
    // already resolved
    const asyncFunc = () => Promise.resolve(2);

    const { result, waitForNextUpdate } = renderHook(() => useAsync(asyncFunc, { initialValue: 1 }));

    expect(result.current.value).toEqual(1);

    await waitForNextUpdate(); // NEVER RESOLVE
});

it('should resolve asynchronous promise', async () => {
    // will resolve in 50ms
    const asyncFunc = () => new Promise(resolve => setTimeout(resolve, 50)).then(() => 2);

    const { result, waitForNextUpdate } = renderHook(() => useAsync(asyncFunc, { initialValue: 1 }));

    expect(result.current.value).toEqual(1);

    await waitForNextUpdate(); // NEVER RESOLVE
});

This is probably related to the first issue - promise is in resolved state already but the value from the promise wasn't set.

[mpeyper]

Can you share the useAsync hook code as well please? (Preferably in a codesandbox)

[kostrse]

I'm sorry, I had intention to post it to react-async, posted by mistake here. I believe the issue is with react-async, not @testing-library/react-hooks.