我如何断言C＃异步方法在单元测试中引发异常？

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可能重复： 如何使用NUnit测试异步方法，最终使用另一个框架？

我想知道的是如何断言异步方法在C＃单元测试中抛出异常？我可以在Visual Studio 2012中使用 Microsoft.VisualStudio.TestTools.UnitTesting 编写异步单元测试，但还没有弄清楚如何测试异常。我知道xUnit也支持这种异步测试方法，虽然我还没有尝试过这个框架。

对于我的意思，代码定义了被测系统：

using System; 使用System.Threading.Tasks; public class AsyncClass { public AsyncClass（）{} public Task< int> GetIntAsync（） { throw new NotImplementedException（）; } }

此代码段定义了一个测试 TestGetIntAsync for AsyncClass.GetIntAsync 。这是我需要输入如何完成 GetIntAsync 抛出异常的断言：

使用Microsoft.VisualStudio.TestTools.UnitTesting; 使用System.Threading.Tasks; [TestClass] public class TestAsyncClass { [TestMethod] public async任务TestGetIntAsync（） { var obj = new AsyncClass（）; //如何断言抛出异常？ var rslt = await obj.GetIntAsync（）; } }

随意使用一些其他相关的单元测试框架Visual Studio一个，如xUnit，如果需要，或者你会认为这是一个更好的选择。

解决方案

请尝试标记方法：

[ExpectedException（typeof（NotImplementedException））] pre>

Possible Duplicate: How do I test an async method with NUnit, eventually with another framework?

What I would like to know is how I can assert that an asynchronous method throws an exception, in a C# unit test? I am able to write asynchronous unit tests with Microsoft.VisualStudio.TestTools.UnitTesting in Visual Studio 2012, but have not figured out how to test for exceptions. I know that xUnit also supports asynchronous test methods in this way, although I haven't tried that framework yet.

For an example of what I mean, the following code defines the system under test:

using System; using System.Threading.Tasks; public class AsyncClass { public AsyncClass() { } public Task<int> GetIntAsync() { throw new NotImplementedException(); } }

This code snippet defines a test TestGetIntAsync for AsyncClass.GetIntAsync. This is where I need input on how to accomplish the assertion that GetIntAsync throws an exception:

using Microsoft.VisualStudio.TestTools.UnitTesting; using System.Threading.Tasks; [TestClass] public class TestAsyncClass { [TestMethod] public async Task TestGetIntAsync() { var obj = new AsyncClass(); // How do I assert that an exception is thrown? var rslt = await obj.GetIntAsync(); } }

Feel free to employ some other relevant unit test framework than the Visual Studio one, such as xUnit, if necessary or you would argue that it's a better option.

解决方案

Please try mark method with:

[ExpectedException(typeof(NotImplementedException))]