Cassini/WebServer.WebDev、NUnit和AppDomainUnloadedException

Question

我使用Cassini/WebServer.WebDev使用NUnit运行一些WebService的自动化测试。

我没做什么花哨的事，只是

public class WebService{
  Microsoft.VisualStudio.WebHost.Server _server;

  public void Start(){
    _server = new Microsoft.VisualStudio.WebHost.Server(_port, "/", _physicalPath);
  }

  public void Dispose()
  {
    if (_server != null)
    {
      _server.Stop();
      _server = null;
    }
  }
}
[TestFixture]
public void TestFixture{
  [Test]
  public void Test(){
    using(WebService webService = new WebService()){
      webService.Start();
      // actual test invoking the webservice
    }
  }
}

，但是当我使用nunit- when e.exe运行它时，我得到了以下输出：

NUnit version 2.5.0.9015 (Beta-2)
Copyright (C) 2002-2008 Charlie Poole.\r\nCopyright (C) 2002-2004 James W. Newki
rk, Michael C. Two, Alexei A. Vorontsov.\r\nCopyright (C) 2000-2002 Philip Craig
.\r\nAll Rights Reserved.

Runtime Environment -
   OS Version: Microsoft Windows NT 6.0.6001 Service Pack 1
  CLR Version: 2.0.50727.1434 ( Net 2.0.50727.1434 )

ProcessModel: Default    DomainUsage: Default
Execution Runtime: net-2.0.50727.1434
.....
Tests run: 5, Errors: 0, Failures: 0, Inconclusive: 0 Time: 28,4538451 seconds
  Not run: 0, Invalid: 0, Ignored: 0, Skipped: 0


Unhandled exceptions:
1) TestCase1 : System.AppDomainUnloadedException: Attempted to access an unloaded AppDomain.
2) TestCase2 : System.AppDomainUnloadedException: Attempted to access an unloaded AppDomain.
3) TestCase3 : System.AppDomainUnloadedException: Attempted to access an unloaded AppDomain.
4) TestCase4 : System.AppDomainUnloadedException: Attempted to access an unloaded AppDomain.

如果我在调试器下运行nunit-控制台，则在调试控制台中得到以下输出：

[...]
The thread 0x1974 has exited with code 0 (0x0).
############################################################################
##############                 S U C C E S S               #################
############################################################################
Executed tests       : 5
Ignored tests        : 0
Failed tests         : 0
Unhandled exceptions : 4
Total time           : 25,7092944 seconds
############################################################################
The thread 0x1bd4 has exited with code 0 (0x0).
The thread 0x10f8 has exited with code 0 (0x0).
The thread '<No Name>' (0x1a80) has exited with code 0 (0x0).
A first chance exception of type 'System.AppDomainUnloadedException' occurred in System.Web.dll
##### Unhandled Exception while running 
System.AppDomainUnloadedException: Attempted to access an unloaded AppDomain.
   at System.Web.Hosting.ApplicationManager.HostingEnvironmentShutdownComplete(String appId, IApplicationHost appHost)
   at System.Web.Hosting.HostingEnvironment.OnAppDomainUnload(Object unusedObject, EventArgs unusedEventArgs)
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in System.Web.dll
The thread 0x111c has exited with code 0 (0x0).
The program '[0x1A64] nunit-console.exe: Managed' has exited with code -100 (0xffffff9c).

有人知道是什么原因造成的吗？

Answer 1

我也有同样的问题，但没有使用卡西尼。相反，我有自己的基于System.Net.HttpListener的web服务器托管，通过ASP.Net支持运行在通过System.Web.Hosting.ApplicationHost.CreateApplicationHost()创建的不同应用程序域中的System.Web.HttpRuntime。这本质上就是Cassini的工作方式，只是Cassini在套接字层工作，并实现了System.Net.HttpListener本身提供的许多功能。

无论如何，为了解决我的问题，在让System.Web.HttpRuntime.Close()卸载我的应用程序域之前，我需要调用NUnit。为此，我在我的主机代理类中公开了一个新的Close()方法，该方法由我的SetupFixture类的TearDown方法调用，该方法调用System.Web.HttpRuntime.Close()。

我通过.Net Reflector查看了Cassini实现，尽管它使用了System.Web.HttpRuntime.ProcessRequest()，但似乎在任何地方都没有调用System.Web.HttpRuntime.Close()。

我不太确定如何继续使用预构建的Cassini实现(Microsoft.VisualStudio.WebHost.Server)，因为您需要在由Cassini创建的应用程序域中调用System.Web.HttpRuntime.Close()以承载ASP.Net。

供参考，这里有一些我的工作单元测试与嵌入式网络托管。

我的WebServerHost类是一个非常小的类，它允许将请求封送到System.Web.Hosting.ApplicationHost.CreateApplicationHost()创建的应用程序域中。

using System;
using System.IO;
using System.Web;
using System.Web.Hosting;

public class WebServerHost :
    MarshalByRefObject
{
    public void
    Close()
    {
        HttpRuntime.Close();
    }

    public void
    ProcessRequest(WebServerContext context)
    {
        HttpRuntime.ProcessRequest(new WebServerRequest(context));
    }
}

WebServerContext类只是一个从System.MarshalByRefObject派生的System.Net.HttpListenerContext实例的包装器，它允许来自新的ASP.Net宿主域的调用返回到我的域中。

using System;
using System.Net;

public class WebServerContext :
    MarshalByRefObject
{
    public
    WebServerContext(HttpListenerContext context)
    {
        this.context = context;
    }

    //  public methods and properties that forward to HttpListenerContext omitted

    private HttpListenerContext
    context;
}

WebServerRequest类只是抽象System.Web.HttpWorkerRequest类的一个实现，它通过WebServerContext类从ASP.Net宿主域调用回我的域中。

using System;
using System.IO;
using System.Web;

class WebServerRequest :
    HttpWorkerRequest
{
    public
    WebServerRequest(WebServerContext context)
    {
        this.context = context;
    }

    //  implementation of HttpWorkerRequest methods omitted; they all just call
    //  methods and properties on context

    private WebServerContext
    context;
}

WebServer类是用于启动和停止web服务器的控制器。启动时，使用我的ASP.Net类作为代理创建WebServerHost托管域，以允许交互。还启动了一个System.Net.HttpListener实例，并启动了一个单独的线程来接受连接。当建立连接时，线程池中将启动一个工作线程来处理请求，同样是通过我的WebServerHost类。最后，当web服务器停止时，侦听器停止，控制器等待接受连接的线程退出，然后侦听器关闭。最后，HTTP运行时也通过调用WebServerHost.Close() 方法(.)关闭。

using System;
using System.IO;
using System.Net;
using System.Reflection;
using System.Threading;
using System.Web.Hosting;

class WebServer
{
    public static void
    Start()
    {
        lock ( typeof(WebServer) )
        {
            //  do not start more than once
            if ( listener != null )
                return;

            //  create web server host in new AppDomain
            host =
                (WebServerHost)ApplicationHost.CreateApplicationHost
                (
                    typeof(WebServerHost),
                    "/",
                    Path.GetTempPath()
                );

            //  start up the HTTP listener
            listener = new HttpListener();
            listener.Prefixes.Add("http://*:8182/");
            listener.Start();

            acceptConnectionsThread = new Thread(acceptConnections);
            acceptConnectionsThread.Start();
        }
    }

    public static void
    Stop()
    {
        lock ( typeof(WebServer) )
        {
            if ( listener == null )
                return;

            //  stop listening; will cause HttpListenerException in thread blocked on GetContext()  
            listener.Stop();

            //  wait connection acceptance thread to exit
            acceptConnectionsThread.Join();
            acceptConnectionsThread = null;

            //  close listener
            listener.Close(); 
            listener = null;

            //  close host
            host.Close();
            host = null;
        }
    }

    private static WebServerHost
    host = null;

    private static HttpListener
    listener = null;

    private static Thread
    acceptConnectionsThread;

    private static void
    acceptConnections(object state)
    {
        while ( listener.IsListening )
        {
            try
            {
                HttpListenerContext context = listener.GetContext();
                ThreadPool.QueueUserWorkItem(handleConnection, context);
            }
            catch ( HttpListenerException e )
            {
                //  this exception is ignored; it will be thrown when web server is stopped and at that time
                //  listening will be set to false which will end the loop and the thread
            }
        }
    }

    private static void
    handleConnection(object state)
    {
        host.ProcessRequest(new WebServerContext((HttpListenerContext)state));
    }
}

最后，这个Initialization类被标记为NUnit SetupFixture属性，用于在单元测试启动时启动web服务器，并在测试完成后关闭它。

using System;
using NUnit.Framework;

[SetUpFixture]
public class Initialization
{
    [SetUp]
    public void
    Setup()
    {
        //  start the local web server
        WebServer.Start();
    }

    [TearDown]
    public void
    TearDown()
    {
        //  stop the local web server
        WebServer.Stop();
    }
}

我知道这并不完全是在回答这个问题，但我希望你能找到有用的信息。