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

St3fan, you are a genius. Thanks a lot!

This is how I did it using your suggestion.

'Downloader' defines a protocol with a method DownloadDidComplete that fires on completion. There's a BOOL member variable 'downloadComplete' that is used to terminate the run loop.

-(void) testDownloader {
 downloadComplete = NO;
 Downloader* downloader = [[Downloader alloc] init] delegate:self];

 // ... irrelevant downloader setup code removed ...

 NSRunLoop *theRL = [NSRunLoop currentRunLoop];

 // Begin a run loop terminated when the downloadComplete it set to true
 while (!downloadComplete && [theRL runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]);

}


-(void) DownloaderDidComplete:(Downloader*) downloader withErrors:(int) errors {
    downloadComplete = YES;

    STAssertNotEquals(errors, 0, @"There were errors downloading!");
}

The run-loop could potentially run forever of course.. I'll improve that later!