为什么在同一测试项目程序集中两次调用[AssemblyInitialize]和[AssemblyCleanup]?

问题描述：

我认为这些属性的全部目的是每个程序集仅运行一次.我有一个简单的类，如下所示:

I thought the whole purpose of these attributes was to run them only once per assembly. I have a simple class as follows:

[TestClass]
public class AssemblyIntegrationTestSetup
{
    public AssemblyIntegrationTestSetup() { }
    public TestContext TestContext { get; set; }

    [AssemblyInitialize]
    public static void SetupIntegrationTests(TestContext context)
    {
         WindowsServiceService.Instance.StartService("Distributed Transaction Coordinator");
    }

    [AssemblyCleanup]
    public static void TeardownIntegrationTests()
    {
          WindowsServiceService.Instance.StopService("Distributed Transaction Coordinator");
    }

}

但是，当我运行测试套件时，程序集级的Initialize和Cleanup方法执行两次.以下是有关我的环境的详细信息:

However when I run the test suite the assembly-level Initialize and Cleanup methods execute twice. Here are the details about my environemnt:

所有测试类都在同一项目/程序集中.
我有按名称空间分隔的集成和单元测试.
对于集成测试，我使用MSTextExtensions允许回滚数据库事务.
我还正在启动/停止MS SQL Server DTC服务，这是回滚功能所必需的.我希望每个测试套件运行一次(并且发现的最佳折衷方法是使用程序集级属性).该代码可以运行，但是执行两次.
如果有关系，我在某些测试中还将使用Microsoft Moles Framework.

观察到的行为类似于:

AssemblyInitialize         

Class1.TestInitialize
Class1.TestMethod1
Class1.TestCleanup

AssemblyInitalize         <-- //This shouldn't be happening right?

Class2.TestInitialize
Class2.TestMethod1
Class2.TestCleanup

Class2.TestInitialize
Class2.TestMethod2
Class2.TestCleanup

Class5.TestInitialize
Class5.TestMethod1
Class5.TestCleanup

Class7.TestInitialize
Class7.TestMethod1
Class7.TestCleanup

//More random bouncing around then...

AssemblyCleanup 
AssemblyCleanup           <-- //This shouldn't be happening right?

答

来自MSDN库文章:

重要

此属性不应在 ASP.NET单元测试，即任何测试 [HostType("ASP.NET")]属性. 由于IIS的无状态性质和ASP.NET，一种用此属性可能被称为更多每次测试运行一次.

This attribute should not be used on ASP.NET unit tests, that is, any test with [HostType("ASP.NET")] attribute. Because of the stateless nature of IIS and ASP.NET, a method decorated with this attribute might be called more than once per test run.

您可以在测试运行器中调整一些旋钮.我只是用一个计数器来解决这个问题:

There are few knobs you can tweak in test runner. I would just punt the problem with a counter:

private int InitCount;

[AssemblyInitialize]
public static void SetupIntegrationTests(TestContext context)
{
     if (InitCount++ == 0) {
         WindowsServiceService.Instance.StartService("Distributed Transaction Coordinator");
     }
}

[AssemblyCleanup]
public static void TeardownIntegrationTests()
{
      if (--InitCount == 0) {
          WindowsServiceService.Instance.StopService("Distributed Transaction Coordinator");
      }
}

为什么在同一测试项目程序集中两次调用[AssemblyInitialize]和[AssemblyCleanup]?

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