Better way of testing asynchronous code?

[ncri]

This works, but is rather ugly because of the try catch block:

suite 'hide_flash', ->
  test 'should hide message div after delay', (done) ->
    $("body").append $('<div>').attr('id', 'message')
    hide_message_after_delay()
    setTimeout ->
      try
        $('#message').is(':hidden').should.be.true
        done()
      catch err
        done err
    , 1000

Is there a better way of doing this? Also, the message when the test fails is not very pretty:

Error: done() invoked with non-Error: "actual error is here"

Related is this mocha pull request I think: mochajs/mocha#278

[matthijsgroen]

Use promises and mocha as promised?

[jfirebaugh]

I would use sinon's fake timers.

[ncri]

Thanks, for the hints. Promises looks, well, promising. :) But I think in this cases fake timers suit really well, I'll give them a try. I still hope though, there is going to be a way built into Mocha to fo asynchronous stuff more cleanly... But I guess it's a Mocha rather then Konacha issue? Or can something be done in Konacha? Otherwise I guess we shall close this?

[matthijsgroen]

I extend mocha (the test runner) with the mocha-as-promised lib (also found in the konacha-chai-matchers gem) and test these things using chai-as-promised, plain .then => assert or the sinon fakeTimers.

All solutions work really well, but I prefer to write all async code as promises :-)

[jfirebaugh]

Yeah, this is a need that 3rd party tools (promises or fake timers) solve pretty well without needing coordination from the testing framework. You could raise it with mocha, but I suspect you'll likely get a similar response there.

[jamesmacwilliam]

in the event that you have an app that relies on a deferred block of code:
I also noticed that if you set the timeout or delay (using underscore) to 1 and put the expectation within the delayed block, the result gets picked up by the suite the same as it otherwise would