removed useless expect.assertions

[Flavien-Pensato]

In a lot of case expect.assertions(1); is no need. It can be confusing.

In fact, we should never use expect.assertions ^^ expect in some case explained by @rickhanlonii .

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[rickhanlonii]

I think this is intentional, from those same docs:

Make sure to add expect.assertions to verify that a certain number of assertions are called. Otherwise a fulfilled promise would not fail the test

[Flavien-Pensato]

@rickhanlonii exactly ! So why should we use expect.assertions(1); even if we are sure to call expect ?

[rickhanlonii]

So I looked a little closer and this change is great - expect.assertions is not needed when using resolves/rejects 👍

To explain a little better and answer your question - when you're using resolves/rejects, we have built in checking for unexpected behavior. So let's say you have this test:

const fetchData = () => Promise.resolve('foo');

test('the fetch fails with an error', () => {
  return expect(fetchData()).rejects.toMatch('error');
});

Then we show this error:

So we tell you that you're expecting it to reject, but it resolved.

Where you need the expect.assertions is when you do your own promise handling, as in the other examples:

const fetchData = () => Promise.resolve('foo');

test('the fetch fails with an error', () => {
  expect.assertions(1);
  return fetchData().catch(e => {
    expect(e).toMatch('error')
  });
});

Here without the expect.assertions then the promise will resolve and the expectations in the .catch block will not run and the test will pass. Using expect.assertions in this case is basically a replacement for adding a .then block that fails

[rickhanlonii]

LGTM

[rickhanlonii]

This needs a changelog entry and it can go

[rickhanlonii]

Thanks @Flavien-Pensato for your first Jest contribution!

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