Testing 对诸如dispatch\u async之类的代码进行单元测试。

需要对以下代码进行单元测试，dispatch_async意味着代码不会按应用程序逻辑顺序执行，您知道如何使其及时运行吗

多谢各位

 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
        [AdTracker dosomething];
    });

看

}

+ (BOOL)waitFor2:(finishBlock)block {
NSTimeInterval timeoutInSeconds = 10.0;
NSDate* giveUpDate = [NSDate dateWithTimeIntervalSinceNow:timeoutInSeconds];

while (!block() && ([giveUpDate timeIntervalSinceNow] > 0)) {
    NSDate *stopDate = [NSDate dateWithTimeIntervalSinceNow:1.0];
    [[NSRunLoop currentRunLoop] runUntilDate:stopDate];   // un-blocking.
    DLog(@"+++++  %@", [NSDate date]);
}   

return block();