Can't use Promise.reject with 'and.returnValues()'

[coyoteecd]

I am trying to spy on an async function that gets called twice; first time I'd like to return a rejected Promise and second time a resolved one. I've read through the comments in #1590; the callFake() is something I use for the simple case where I just want to just return a rejected promise all the time. But that won't work with multiple calls.

Of course, one workaround is to use callFake() in combination with a counter in the test spec and conditionally return a resolved/rejected promise based on the counter. But this reduces the test readability and is just a pain to do more than once. I feel the library should provide a better way.

Expected Behavior

One option could be to introduce a callFakes() that accepts multiple callbacks and calls them in order, similar to what .and.returnValues() does. This way I can conveniently write:

spyOn(obj, 'asyncMethod').and.callFakes(
 () => Promise.reject('bad'),
 () => Promise.resolve()
);

which in my opinion looks good and can even be used for other things.

Note: after writing this I did a search on callFakes and it turned out this has been proposed before, see #1688 (comment). Would this be something we want in jasmine then?

[slackersoft]

If possible, I'd still like to see something more general (as I mentioned). This would also allow mixing and matching strategies, instead of requiring the use of a full fake function. To bring those suggestions inline here too, something like:

request.get.and.rejectWith(new Error('404'))
    .andThen.rejectWith(new Error('404'))
    .andThen.resolveTo('OK')

or:

request.get.and.do(
  (call) => call.rejectWith(new Error('404')),
  (call) => call.rejectWith(new Error('404')),
  (call) => call.resolveTo('OK')
)

The first option feels more fluent, but will probably be more complicated to implement. I think either would be fine and I'm happy to discuss what feels better to the community as well.