fetchMock.mock.calls never updates (possibly jest 26)

[green-arrow]

After upgrading our codebase to jest 26 and this library to 1.5.1, our tests that used the .toHaveBeenCalled assertions stopped working. It appears that the .mock property is never updated with the calls to the spy.

I tried digging into the code a bit, and it seems like this wrapper does the Object.assign(jestifiedInstance.mock, spy.mock) only once, so those aren't kept in sync. Unfortunately fetchMock.mock is also a method, so we can't just assign jestifiedInstance.mock = spy.mock.

I tinkered around with the code locally and got something working by handling the fetchHandler and mock inside the proxy. It seems to run on our codebase without issue. I'd be happy to spin up a PR if you're interested!

[wheresrhys]

Yep that would be good - thanks

[alexpovh]

Same issue here, happens only when clearMocks is set to true in jest configuration.

[SpencerKaiser]

Just to add onto the content above, I'm having the exact same issue... I have clearMocks enabled in my Jest config and I spent the last two hours debugging this:

// ✅
expect(fetchMock).toHaveLastFetched(
  onboardingEndpoint,
  expect.objectContaining({
    method: 'POST',
    headers: {
      'content-type': 'application/json',
    },
    body: JSON.stringify({ name }),
  }),
);

// ❌
expect(fetch).toHaveBeenCalled();

// ✅
expect(fetchMock).toHaveLastFetched(onboardingEndpoint);

// ❌
expect(fetchMock).toHaveLastFetched(expect.anything());

So yea... that was quite rough 😅 @wheresrhys do you think that last example is related? If not or if you aren't sure, I'll open up a new issue for it.

[th3fallen]

same here, but removing clearMocks in our config is a no go as our tests go BANANAS