如何等待NSOperationQueue在单元测试中完成？ [英] How do I wait until an NSOperationQueue has finished in a Unit Test?

问题描述

问题

• 我有一个NSOperationQueue logEntryGeneratorQueue


• 我要等待队列上的所有操作完成

我使用：

[logEntryGeneratorQueue waitUntilAllOperationsAreFinished];

如果添加到队列的线程在后台本身，它工作正常。

it works fine if the thread adding to the queue is in the background itself.

但是，如果我通过单元测试运行这个代码，它将在主线程上运行。所以我
想出了这个解决方案，我真的不喜欢：

However, if I'm running this code via a unit test, it'll be running on the main thread. So I came up with this "solution", which I really don't like:

if ([NSThread isMainThread]) {
    while ([[logEntryGeneratorQueue operations] count] > 0) {
        [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:1]];
    }
} else {
    [logEntryGeneratorQueue waitUntilAllOperationsAreFinished];
}

这总是不太理想，但总是在10.5上正常工作。但是，现在我已经将我的项目升级到使用10.6 SDK，这打破了。

This was always less than ideal, but has always worked fine on 10.5. However, now I've upgraded my project to using the 10.6 SDK, and this breaks.

在一个测试中，它实际上在完成之前退出测试。我不知道为什么 - 我认为这是与NSOperationQueues工作方式不同的方式在10.6 - 他们现在使用GCD。

On one test, it actually quit the test before it completed. I've no idea why - I assume it's something to do with the way NSOperationQueues work differently in 10.6 - they now use GCD.

我试过的

What I've Tried

我试过用sleep替换runUntilDate，正如我想的，这意味着每个测试都会在这里暂停。

I've tried replacing the runUntilDate with sleep, which, as I thought, means every test pauses forever when it gets here.

我的问题

是否有更好的方法等待NSOperationQueue在主线程上完成？

Is there a better way to wait for an NSOperationQueue to finish on a main thread? If not, how can I get this code working under 10.6?

推荐答案

解决方案

我意识到我的代码是在一个永恒的循环，因为我在主线程调用 mergeChangesFromContextDidSaveNotification ，同时也等待队列完成主线程。因为合并更改在 waitUntilAllOperationsAreFinished 后调用，所以它从未被执行。

I realised that my code was in an eternal loop because I was calling mergeChangesFromContextDidSaveNotification on the main thread whilst also waiting for the queue to finish on the main thread. And since the merge changes was called after waitUntilAllOperationsAreFinished, it never got executed.

我认为答案是更改我从哪里运行NSOperationQueues。我不应该运行一个NSOperationQueue处理核心数据东西在主线程。我不应该真的在主线程上运行这个密集的东西，因为性能的原因，无论如何，我猜。

I think the answer is to change where I run NSOperationQueues from. I shouldn't run an NSOperationQueue that deals with core data stuff on the main thread. And I shouldn't really be running this intensive stuff on the main thread for performance reasons anyway I guess.

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