Making assertions about how the mock was used

[elastic]

Making assertions about how the mock was used

[delvedor]

Hello! Currently, it's not possible, but it would be a nice feature!
It should be opt-in in my opinion, so if a user want to use a different mock method (jest.fn for example), they can do it.
Would you like to work on it? :)

[iamEAP]

For future wanderers who find themselves here: a trick I used to get this functionality is as follows:

const deleteSpy = jest.fn().mockReturnValue({});
mock.add({
  method: 'DELETE',
  path: '/some-specific-index-name',
}, deleteSpy);

await client.indices.delete({
  index: 'some-specific-index-name',
});

expect(deleteSpy).toHaveBeenCalled();

It's not great, because a failure doesn't make a distinction between "wasn't actually called at all" and "was called with the wrong index name." You could work around this by matching any index and asserting the shape of the call to the deleteSpy, but it's quite verbose.

Naturally, the same approach (of passing a spy with mock implementation as the response body getter) will work on any method/path.