MsTest and OWIN, duplicated controller - visual-studio

Question

I have a set of integration tests executed by MsTest around OWIN, using the OWIN startup method for self host.
The tests are quite simple and use the following pattern:
WebApp.Start<Startup>(url: appAddress);
HttpClient client = new HttpClient();
client.DefaultRequestHeaders
.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var response = client.GetAsync(uri).Result;
When I run the test on our local DEV machines, they are green.
When we run the test from Visual Studio inside our Build Machine, they are green.
If they run from the queue, few days ago, we started to get this annoying error from OWIN:
*** 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()"}
And this is strange because we use Windsor to resolve the controllers and we also print out the registrations in Windsor and of course there is only one controller with that name. We have this issue on all the controllers only if the code is executed within MsBuild ... Inside Visual Studio of the Build Machine or in production, it works.
Could be that the error is something else but swallowed by OWIN?

Answer 1

I was getting the same error and In my case it was a combination of factors:
I'm using Nunit and Owin for selfhosting.
In the setup of the tests I start web server:
_server = WebApp.Start<Startup>(new StartOptions(baseAddress));
In the teardown of the tests I kill it:
_server.Dispose();
One of my tests was using TestCaseSource which is executed before the setup:
[TestCaseSource(typeof(TestData), "TestDataSource")]
public void Test_With_Source(TestData testcase)
Down the line, inside TestData.TestDataSource I was loading the assembly that contains the controllers to get some route information:
loadedAssembly = Assembly.LoadFile(dll); //First load of the assembly
At the point where the the web server was started (on the setup) the assembly was loaded once already (by the TestCaseSource) so I end up with the same assembly twice and web api complaining about a duplication of the same controller.
My fix was to remove the Assembly.LoadFile(dll) by:
typeof(BaseController).Assembly
That made the assembly containing the BaseController not been loaded twice.

Answer 2

We solved the problem in our tests by hosting the OWIN project within IIS express
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();
}
}
}