How to unit test asynchronous APIs?

Question

I have installed Google Toolbox for Mac into Xcode and followed the instructions to set up unit testing found here.

It all works great, and I can test my synchronous

Answer 1

This is tricky. I think you will need to setup a runloop in your test and also the ability to specify that runloop to your async code. Otherwise the callbacks won't happen since they are executed on a runloop.

I guess you could just run the runloop for s short duration in a loop. And let the callback set some shared status variable. Or maybe even simply ask the callback to terminate the runloop. That way you you know the test is over. You should be able to check for timeouts by stoppng the loop after a certain time. If that happens then a timeout ocurred.

I've never done this but I will have to soon I think. Please do share your results :-)