Add promises-aplus tests for the promise library

[forivall]

I was curious if the promise implementation you have is Promises/A+ conformant, and unfortunately, it's not, since it appears to be more of a jquery promise-compatible, which does some things synchronously that should be async.

The results summary:

266 passing (2m) 592 failing

[josdejong]

Thanks for your inputs Emily. The reason we couldn't use a standard Promise library (or nowadays the Promise implementation built in JS itself) is that we need support for cancellation. So I think it will not be possible to get the workerpool version of Promise standards compliant, though we could set some steps in that direction I guess.

What we could do is rename the (internal) Promise class to CancellablePromise or something like that to make it more clear that it's not a standard Promise implementation.

What do you think?

[forivall]

Yup, i totally understand the need for cancellation.

Renaming makes sense, and another option would be to extend the native promise type, such as in https://github.com/sindresorhus/p-cancelable . Although, I also don't know if you need the tight control over synchronicity from your custom promise implementation.

[josdejong]

It would be nice to see if we can replace Promise implementation with an external library like p-cancelable. I'm not sure if there would be incompatibilities and if it's possible to achieve or not, but it may be worth an experiment. Anyone interested in trying this out?