Example of writing an OCUnit test that uses asynchronous methods by polling for completion

gistfile1.m

#define POLL_INTERVAL 0.05 //50ms
#define N_SEC_TO_POLL 1.0 //poll for 1s
#define MAX_POLL_COUNT N_SEC_TO_POLL / POLL_INTERVAL

- (void) testAnAsynchronousFunction
{
    __block BOOL done = NO;
    
    //do async on a delay
    float delayInSeconds = 0.5;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_current_queue(), ^(void){
        BOOL result = dosomething(); //do the actual logic
        STAssertTrue(result, @"this would be whatever needed testing");
        done = YES;
    });

    NSLog(@"started poll");
    NSUInteger pollCount = 0;
    
    while (done == NO && pollCount < MAX_POLL_COUNT) {
        NSLog(@"polling... %i", pollCount);
        NSDate* untilDate = [NSDate dateWithTimeIntervalSinceNow:POLL_INTERVAL]; 
        [[NSRunLoop currentRunLoop] runUntilDate:untilDate];
        pollCount++;
    }
    if (pollCount == MAX_POLL_COUNT) {
        STFail(@"polling timed out");
    }
    
    NSLog(@"done polling");
}