c# - Rhino Mocks - Arg<T> to ommit some parameters -

i using rhino mocks stub out functionality of soap endpoint , part works. but, interface quite quirky , struggling following work (i have renamed classes simplicity)

  public interface iwebservice     {         void copyfile(request request);     }  public interface iservice {     void copyfile(string filename, byte[] data); }  public class request {     public string filename { get; set; }     public byte[] data { get; set; } } public class service : iservice {     iwebservice _service;     public service(iwebservice service)     {         _service = service;     }     public void copyfile(string filename, byte[] data)     {         _service.copyfile(new request() {filename = filename,data = data });     } } 

now, in test have this

[testcase]         public void testfilecopyfailsiffilenameismissing()         {             iwebservice servicemock = mockrepository.generatemock<iwebservice>();             servicemock.expect(x => x.copyfile(arg<request>.is.equal(new request() { filename = arg<string>.is.null, data = arg<byte[]>.is.anything }))).throw(new exception());              service service = new service(servicemock);             service.copyfile(null, new byte[] { });          } 

which throws exception: exception of type 'system.invalidoperationexception' occurred in rhino.mocks.dll not handled in user code

additional information: use arg within mock method call while recording. 1 arguments expected, 3 have been defined.

i have tried possibilities in world on one, cant right. if dont use arg , use

expect(null, new byte[]{}); 

it pass no matter what

i suggest use whencalled , in method check request object.

        bool iscorrectparam = false;          iwebservice servicemock = mockrepository.generatemock<iwebservice>();           servicemock.expect(x => x.copyfile(null))               .ignorearguments()               .whencalled(x =>               {                   request req = x.arguments[0] request;                   if (req.data.count() == 0 && req.filename == null)                   {                       iscorrectparam = true;                   }               });          service service = new service(servicemock);         service.copyfile(null, new byte[] { });          assert.istrue(iscorrectparam);