Sinon: stub().onCall().returns() should return stub function

[zuzusik]

let a = sinon.stub().returns(12); // a is a stub function
let b = sinon.stub().onCall(0).returns(12); // b is not a stub function (but some object)

• Sinon version : 1.17.4

[fatso83]

Not sure what this is. It certainly is not a bug, because those chainable methods have never returned a stub AFAIK, so perhaps this is a feature request? If so, I would suggest you try modifying this yourself and submit a PR that keeps the current API.

Maybe some of the other maintainers know something about the history of this api, and if doing so is a bad idea.

You basically want to avoid having to write the first line in this code:

let b = sinon.stub();
b.onCall(0).returns(12).onCall(1).returns(3);

Not sure if this is worth keeping open just to save you a line, so I am going to close this until further.

[mvcds]

But I'm sure it has worked in the past, I've use it in another project.

[fatso83]

If either @zuzusik or @mvcds can report a version of Sinon where a stub was being returned we have something to work with, as that means we have a regression on our hands. I'll keep it closed until so.

[fatso83]

This might be related to #817, #823 and the PRs #1207 and #1209.

[zuzusik]

@fatso83 just investigated a bit, seems like this behavior exists from the very beginning of the implementation of .onCall() (v 1.8)

Also I noticed that this code works as expected:

let c = sinon.stub().returns(12); // a is a stub function
let b = sinon.stub().onCall(0).returns(12).stub.onCall(1).returns(13).stub; // b is also a stub function

this means that probably returns (and other behavior methods) should return not this, but this.stub || this - as far as I see this will guarantee consistency of this methods when being called either directly from stub, or in .onCall chain

what do you think?

[mvcds]

@fatso83 I am using [email protected] where it behaved as @zuzusik reported.

Separating the code into two lines did the trick though I personally think it does not make as much sense as chaining.

Let me know if I can help you guys with something, I'm new to open source and I'm kind of lost on what or how I can do.

[fatso83]

@mvcds, we can ALWAYS need a hand in fixing stuff. There are more issues than spare time ;-) The biggest obstacle is often getting to the next step, because getting stuck in discussions on finer technical points is easy. So if you want to take a look at the mentioned issues and see if you can see where to go from here that could help in this specific case.

Other than that, just take a gander at the issue list, see if there are any low hanging fruits that would be easy to fix, and then create a pulk request with a fix.