如何单元测试异步API的？ [英] How to unit test asynchronous APIs?

问题描述

我已经安装了谷歌工具箱为Mac 的成X $ C $Ç并按照说明设置单元测试发现这里。

这一切的伟大工程，我可以测试我的所有对象的精绝我的同步方法。然而，大多数复杂的API其实我是想通过调用一个委托的方法异步测试返回结果 - 例如一个文件的下载和更新系统的调用将立即返回，然后运行-fileDownloadDidComplete：方法时，该文件完成下载

我将如何测试这个作为一个单元测试？

好像我会想的testDownload功能，或至少测试框架，以等待为fileDownloadDidComplete：方法来运行

编辑：我现在已经切换到使用X code内置XCTest系统，并发现 TVRSMonitor 在Github上提供了使用信号灯等待异步操作完成死简便的方法。

例如：

   - （无效）{TESTLOGIN
  TRVSMonitor *显示器= [TRVSMonitor显示器]
  __block的NSString * theToken;  [Server实例] loginWithUsername：@foo的密码：@栏
                               成功：^（* NSString的令牌）{
                                   theToken =记号。
                                   [显示器信号]
                               }                               失败：^（NSError *错误）{
                                   [显示器信号]
                               }];  [显示器等];  XCTAssert（theToken，@获得令牌）;
}
 

解决方案

我遇到了同样的问题，发现了不同的解决方案，对我的作品。

我用的是老派的方法通过使用信号量，如下转向异步操作成同步流：

  //创建一个将执行异步操作的对象
MyConnection的*康恩= MyConnection的新]
STAssertNotNil（康涅狄格州，@MyConnection的初始化失败）;//创建信号量并锁定我们开始之前一次
//异步操作
NSConditionLock * TL = [NSConditionLock新]
self.theLock = TL;
[TL发布]//开始异步操作
self.testState = 0;
[康恩doItAsyncWithDelegate：个体经营];//现在锁定信号 - 这将阻止该线程直到
// [self.theLock unlockWithCondition：1]被调用
[self.theLock lockWhenCondition：1];//确保异步回调并实际上是由发生
//检查它是否修改的变量
STAssertTrue（！self.testState = 0，@代表没有得到所谓的）;//我们就大功告成了
[self.theLock发布] self.theLock =零;
[康恩发布]
 

确认调用

  [self.theLock unlockWithCondition：1];
 

在委托（S）即可。

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 methods on all my objects absolutely fine. However, most of the complex APIs I actually want to test return results asynchronously via calling a method on a delegate - for example a call to a file download and update system will return immediately and then run a -fileDownloadDidComplete: method when the file finishes downloading.

How would I test this as a unit test?

It seems like I'd want to the testDownload function, or at least the test framework to 'wait' for fileDownloadDidComplete: method to run.

EDIT: I've now switched to using the XCode built-in XCTest system and have found that TVRSMonitor on Github provides a dead easy way to use semaphores to wait for async operations to complete.

For example:

- (void)testLogin {
  TRVSMonitor *monitor = [TRVSMonitor monitor];
  __block NSString *theToken;

  [[Server instance] loginWithUsername:@"foo" password:@"bar"
                               success:^(NSString *token) {
                                   theToken = token;
                                   [monitor signal];
                               }

                               failure:^(NSError *error) {
                                   [monitor signal];
                               }];

  [monitor wait];

  XCTAssert(theToken, @"Getting token");
}

解决方案

I ran into the same question and found a different solution that works for me.

I use the "old school" approach for turning async operations into a sync flow by using a semaphore as follows:

// create the object that will perform an async operation
MyConnection *conn = [MyConnection new];
STAssertNotNil (conn, @"MyConnection init failed");

// create the semaphore and lock it once before we start
// the async operation
NSConditionLock *tl = [NSConditionLock new];
self.theLock = tl;
[tl release];    

// start the async operation
self.testState = 0;
[conn doItAsyncWithDelegate:self];

// now lock the semaphore - which will block this thread until
// [self.theLock unlockWithCondition:1] gets invoked
[self.theLock lockWhenCondition:1];

// make sure the async callback did in fact happen by
// checking whether it modified a variable
STAssertTrue (self.testState != 0, @"delegate did not get called");

// we're done
[self.theLock release]; self.theLock = nil;
[conn release];

Make sure to invoke

[self.theLock unlockWithCondition:1];

In the delegate(s) then.

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