用RhinoMocks模拟参考参数

Question

I my code, I have the following call:

 string proposed=string.Empty;
 validator.IsValid(arg0, arg1, ref proposed);

I stub the validator in my test and want that stub to alter the content of the referenced proposed string variable. I tried setting the value of the argument in the WhenCalled-Handler, but this shows no effect.

validatorStub.Stub(x => x.IsValid(arg0, arg1, ref proposed))
                                            .IgnoreArguments()
                                            .WhenCalled(invocation =>
                                            {
                                                invocation.Arguments[2] = "123456"; 
                                            }).Throw(new ValidationException(string.Empty));

Is this possible with Rhino at all? Unfortunately, I have no way of editing that validator...

EDIT: Thanks to @FireAlkazar, I understood that I had to better illustrate my test situtation:

Method Code:

public class ClassUnderTest
{
   public string Arg0{get;set;}
   public string Arg1{get;set;}
   public IValidator Validator {get;set;}

   public bool Validate()
   {
      string proposal = string.Empty;
      try
      {
         if (Validator.IsValid(Arg0, Arg1, ref proposal)) return true;
      }
      catch (ValidationException ex)
      {
         if (!string.IsNullOrEmpty(proposal))
         {
            // I want to test this section of code
         }
      }
      return false;
   }                   
}

Test Code:

[TestMethod]
public void Test_Validate_ValidatorProposes_ReturnsTrue()
{
    string arg0 = "123456789";
    string arg1 = "201208150030551ABC";
    string prop = "123456";

    ClassUnderTest testInstance = new ClassUnderTest();
    testInstance.Arg0 = arg0;
    testInstance.Arg1 = arg1;

    IValidator validatorStub = MockRepository.GenerateStub<IValidator>();
    validatorStub.Stub(x => x.IsValid(Arg<string>.Is.Equal(arg0),
                                      Arg<string>.Is.Equal(arg1),
                                      ref Arg<string>.Ref(Is.Anything(), prop).Dummy))
                 .Throw(new ValidationException(string.Empty));
    testInstance.Validator = validatorStub;

    bool actual = testInstance.Validate();

    Assert.IsFalse(actual);
}

Still, when I step through this, I see that the ValidatorStub throws the exception i expect it to throw, but never sets the ref parameter.

---

EDIT : This branch of RhinoMocks uses a newer version of Castle Core, which solves the issue. The author was kind enough to inform me about this via Google Groups.

Answer 1

Documentation for this case Rhino Mocks 3.5 Out and Ref arguments

Looks like you will have something like

validatorStub.Stub(x => x.IsValid(Arg<string>.Is.Anything, Arg<string>.Is.Anything, ref Arg<string>.Ref(Rhino.Mocks.Constraints.Is.Anything(), "123456").Dummy));

string testRefValue = "";
validatorStub.IsValid("1", "2", ref testRefValue);
Assert.AreEqual("123456", testRefValue);

EDIT:
Had an investigation on your case. Final result is no, can't do that in latest version of Rhino Mocks(3.6). The reason is a bug in old version of Castle.DynamycProxy, that is used by mocks.

Proof:
fix bug: ref & out parameter can not received if Proxied Method throw an
this fix adds lines to Castle.Core/DynamicProxy/Generators/InvocationTypeGenerator.cs like this:

bool hasByRefArguments = false;

//...

if (hasByRefArguments) 
{
    invokeMethodOnTarget.CodeBuilder.AddStatement(new TryStatement());
}

//...

Add in reflector for Rhino.Mocks.dll there is no extra handling for hasByRefArguments case(see same file InvocationTypeGenerator.cs).