Async Unit Testing Helper Method

waitForCompletion.m

# found at http://www.infinite-loop.dk/blog/2011/04/unittesting-asynchronous-network-access/

- (BOOL)waitForCompletion:(NSTimeInterval)timeoutSecs {
    NSDate *timeoutDate = [NSDate dateWithTimeIntervalSinceNow:timeoutSecs];
 
    do {
        [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:timeoutDate];
        if([timeoutDate timeIntervalSinceNow] < 0.0)
            break;
    } while (!done);
 
    return done;
}