November 2020
Intermediate to advanced
226 pages
5h 34m
Chinese
Content preview from C#并发编程经典实例（第2版）
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78
｜
第
7
章
他们都害怕测试并发代码，而且普遍认为这难以实现。然而，就像本章示例所展示的那
样，对并发代码执行单元测试并没有想象中那么困难。现代化的功能和库，比如
async
和
System.Reactive
，已经对测试做了充分考量，且效果显著。可以参考本章示例编写单元测
试，这样做对并发方面的新手尤其有用。（对新手而言，并发代码看起来既复杂又可怕。）
7.1
对
async
方法进行单元测试
问题
假设需要对某个
async
方法进行单元测试。
解决方案
大多数现代单元测试框架支持
async Task
单元测试方法，包括
MSTest
、
NUnit
、
xUnit
。从
Visual Studio 2012
起，
MSTest
开始支持这些测试，如果使用别的单元测试框架，那么需要
升级到最新版本。
以下示例展示了
async
MSTest
单元测试：
[TestMethod]
public async
Task MyMethodAsync_ReturnsFalse()
{
var
objectUnderTest = ...;
bool
result =
await
objectUnderTest.MyMethodAsync();
Assert.IsFalse(result);
}
单元测试框架会留意到方法的返回类型是
Task
，然后自动等待任务完成，并将测试标记为
“成功”或“失败”。
如果所采用的单元测试框架不支持
async Task
单元测试，则需要借助一些辅助操作，等待
被测试的异步操作。有一种选项是使用
GetAwaiter().GetResult() ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.