MsTest 和 OWIN，复制控制器

Question

我有一组由 MsTest 围绕 OWIN 执行的集成测试，使用 OWIN 启动方法进行自我主机。 测试非常简单，使用以下模式：

WebApp.Start<Startup>(url: appAddress);
HttpClient client = new HttpClient();
client.DefaultRequestHeaders
    .Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var response = client.GetAsync(uri).Result;

当我在本地 DEV 机器上运行测试时，它们是绿色的。 当我们在 Build Machine 中从 Visual Studio 运行测试时，它们是绿色的。 如果他们从队列中运行，几天前，我们开始从 OWIN 收到这个烦人的错误：

    *** OWIN STARTED ***
    {"Message":"An error has occurred.",
"ExceptionMessage":"Multiple types were found that match the controller named 'xxx'. 
This can happen if the route that services this request ('odata/v1/{*odataPath}') found multiple controllers defined with the same name but differing namespaces, which is not supported.
The request for 'xxx' has found the following matching controllers:
namespace.V1.Controllers.xxxController
namespace.V1.Controllers.xxxController",
"ExceptionType":"System.InvalidOperationException","StackTrace":"   at System.Web.Http.Dispatcher.DefaultHttpControllerSelector.SelectController(HttpRequestMessage request)
at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()"}

这很奇怪，因为我们使用 Windsor 来解析控制器，并且我们还打印出 Windsor 中的注册信息，当然只有一个具有该名称的控制器。只有在 MsBuild 中执行代码时，我们才会在所有控制器上遇到这个问题……在 Build Machine 的 Visual Studio 中或在生产中，它可以工作。 可能是错误是其他东西，但被 OWIN 吞噬了？

Answer 1

我遇到了同样的错误，就我而言，这是多种因素的结合：

我正在使用 Nunit 和 Owin 进行自托管。 在测试的设置中，我启动了 Web 服务器：

_server = WebApp.Start<Startup>(new StartOptions(baseAddress));

在测试的拆解中我杀死了它：

_server.Dispose();

我的一个测试是使用在设置之前执行的 TestCaseSource：

[TestCaseSource(typeof(TestData), "TestDataSource")]
public void Test_With_Source(TestData testcase)

在 TestData.TestDataSource 内部，我正在加载包含控制器的程序集以获取一些路由信息：

loadedAssembly = Assembly.LoadFile(dll); //First load of the assembly

在 Web 服务器启动时（在设置中），程序集已经加载了一次（由 TestCaseSource），所以我最终得到了两次相同的程序集，并且 web api 抱怨同一个控制器的重复。

我的解决方法是通过以下方式删除 Assembly.LoadFile(dll)：

typeof(BaseController).Assembly

这使得包含 BaseController 的程序集没有被加载两次。

Answer 2

我们通过在 IIS express 中托管 OWIN 项目解决了测试中的问题

public class IisExpressRunner : IDisposable
{
     /// <summary>
     ///   Stores whether this instance has been disposed.
     /// </summary>
     private Boolean _isDisposed;

     /// <summary>
     ///   Stores the IIS Express process.
     /// </summary>
     private Process _process;

     /// <summary>
     /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
     /// </summary>
     public void Dispose()
     {
         Dispose(true);
         GC.SuppressFinalize(this);
     }

     /// <summary>
     /// Starts IIS Express using the specified directory path and port.
     /// </summary>
     /// <param name="configPath">
     /// The directory path.
     /// </param>
     /// <param name="siteName">
     /// The port.
     /// </param>
     public void Start(String configPath, string siteName)
     {
         String iisExpressPath = DetermineIisExpressPath();
         String arguments = String.Format(
        CultureInfo.InvariantCulture, "/config:\"{0}\" /site:{1}", configPath, siteName);

         ProcessStartInfo info = new ProcessStartInfo(iisExpressPath)
         {
            WindowStyle = ProcessWindowStyle.Hidden,
            ErrorDialog = true,
            LoadUserProfile = true,
            CreateNoWindow = false,
            UseShellExecute = false,
            Arguments = arguments
        };

        Thread startThread = new Thread(() => StartIisExpress(info))
        {
            IsBackground = true
        };

        startThread.Start();
     }

     /// <summary>
     /// Releases unmanaged and - optionally - managed resources.
     /// </summary>
     /// <param name="disposing">
     /// <c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.
     /// </param>
     protected virtual void Dispose(Boolean disposing)
     {
         if (_isDisposed)
         {
             return;
         }

        if (disposing)
        {
            // Free managed resources
            if (_process.HasExited == false)
            {
                _process.CloseMainWindow();
            }

            _process.Kill();
            _process = null;
        }

        // Free native resources if there are any
        _isDisposed = true;
    }

     /// <summary>
     /// Determines the IIS express path.
     /// </summary>
     /// <returns>
     /// A <see cref="String"/> instance.
     /// </returns>
     private static String DetermineIisExpressPath()
     {
        String iisExpressPath;

        if (Environment.Is64BitOperatingSystem)
        {
            iisExpressPath = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86);
        }
        else
        {
            iisExpressPath = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
        }

        iisExpressPath = Path.Combine(iisExpressPath, @"IIS Express\iisexpress.exe");

        return iisExpressPath;
    }

     /// <summary>
     /// Starts the IIS express.
     /// </summary>
     /// <param name="info">
     /// The info.
     /// </param>
     [SuppressMessage("Microsoft.Design", "CA1031:DoNotCatchGeneralExceptionTypes",
    Justification = "Required here to ensure that the instance is disposed.")]
     private void StartIisExpress(ProcessStartInfo info)
     {
        try
        {
            _process = Process.Start(info);
            _process.WaitForExit();
        }
        catch (Exception)
        {
            Dispose();
        }
    }
}