How do I reset the result for a property in a stub without resetting the entire stub?

Question

I'm new to Rhino Mocks, so I may be missing something completely.

Lets say I have an interface with has a half dozen properties:

public interface IFoo {
  string Foo1 { get; } // Required non-null or empty
  string Foo2 { get; } // Required non-null or empty
  string Foo3 { get; }
  string Foo4 { get; }
  int Foo5 { get; }
  int Foo6 { get; }
}

And an implementation which takes a similar object but without the same constraints and creates an IFoo instance:

public interface IFooLikeObject {
  string FooLikeObject1 { get; } // Okay non-null or empty
  string FooLikeObject2 { get; } // Okay non-null or empty
  string FooLikeObject3 { get; }
  string FooLikeObject4 { get; }
  string FooLikeObject5 { get; } // String here instead of int
  string FooLikeObject6 { get; } // String here instead of int
}

public class Foo : IFoo {
  public Foo(IFooLikeObject fooLikeObject) {

    if (string.IsNullOrEmpty(fooLikeObject.Foo1)) {
      throw new ArgumentException("fooLikeObject.Foo1 is a required element and must not be null.")
    }

    if (string.IsNullOrEmpty(Foo2)) {
      throw new ArgumentException("fooLikeObject.Foo2 is a required element and must not be null")
    }

    // Make all the assignments, including conversions from string to int...

  }
}

Now in my tests I want to test both that the exceptions are thrown at the proper times and also the exceptions thrown during failed conversions from string to int.

So I need too stub out IFooLikeObject to return valid values for the values I'm not currently testing, and since I don't want to duplicate this code in every test method I extract it out into a seperate method.

public IFooLikeObject CreateBasicIFooLikeObjectStub(MockRepository mocks) {
  IFooLikeObject stub = mocks.Stub<IFooLikeObject>();

  // These values are required to be non-null
  SetupResult.For(stub.FooLikeObject1).Return("AValidString");
  SetupResult.For(stub.FooLikeObject2).Return("AValidString2");
  SetupResult.For(stub.FooLikeObject5).Return("1");
  SetupResult.For(stub.FooLikeObject6).Return("1");
}

This works well enough for testing Foo3 and Foo4, but when testing Foo1, 2, 5, or 6 I get:

System.InvalidOperationException : The result for IFooLikeObject.get_FooLikeObject1(); has already been setup. Properties are already stubbed with PropertyBehavior by default, no action is required

For example:

[Test]
void Constructor_FooLikeObject1IsNull_Exception() {
  MocksRepository mocks = new MocksRepository();
  IFooLikeObject fooLikeObjectStub = CreateBasicIFooLikeObjectStub(mocks);

// This line causes the exception since FooLikeObject1 has already been set in CreateBasicIFooLikeObjectStub()
  SetupResult.For(fooLikeObjectStub.FooLikeObject1).Return(null); 

  mocks.ReplayAll();

  Assert.Throws<ArgumentException>(delegate { new Foo(fooLikeObjectStub); });
}

How can I set it up so that I can override an individual property which already has a return value set up without having to redo all the others as well?

Answer 1

I might be missing something, but have you tried just doing this?

var stub = mocks.Stub<IFooLikeObject>();

stub.FooLikeObject1 = "AValidString";
stub.FooLikeObject2 = "AValidString2";
stub.FooLikeObject5 = "1";
stub.FooLikeObject6 = "1";

With stubs, you can just set the properties to what you want them to be directly.

If the property is read only you could do it like this:

var stub = mocks.Stub<IFooLikeObject>();

stub.Stub( x => x.FooLikeObject1).Return("AValidString");
stub.Stub( x => x.FooLikeObject2).Return("AValidString2");
stub.Stub( x => x.FooLikeObject5).Return("1");
stub.Stub( x => x.FooLikeObject6).Return("1");

Answer 2

This can be done using the Repeat.Any() construct.

I have not tested this using the SetupResult.For Syntax, but it works with the lambda syntax:

public IFooLikeObject CreateBasicIFooLikeObjectStub(MockRepository) {
  IFooLikeObject stub = MockRepository.GenerateStub<IFooLikeObject>();

  // These values are required to be non-null
  stub.Stub(s => s.FooLikeObject1).Return("AValidString");
  stub.Stub(s => s.FooLikeObject2).Return("AValidString2");
  stub.Stub(s => s.FooLikeObject5).Return("1");
  stub.Stub(s => s.FooLikeObject6).Return("1");
}

[Test]
void Constructor_FooLikeObject1IsNull_Exception() {
  IFooLikeObject fooLikeObjectStub = CreateBasicIFooLikeObjectStub();

  // This line no longer causes an exception
  stub.Stub(s => s.FooLikeObject1).Return(null).Repeat.Any(); // The Repeat.Any() is key. Otherwise the value wont be overridden.

  Assert.Throws<ArgumentException>(delegate { new Foo(fooLikeObjectStub); });
}

The only caveat I've found is you can't do it twice.