Argument captures with Rhino.Mocks

ThingTest.cs

using System;
using NUnit.Framework;
using Rhino.Mocks;

namespace Thing
{
    public class Thing
    {
        private readonly IMesasgeService _messageService;

        public Thing(IMesasgeService messageService)
        {
            _messageService = messageService;
        }

        public void DoIt(string name)
        {
            _messageService.DoSomething(broadcaster => 
                broadcaster.BroadcastMessage(string.Format("Hello, {0}", name)));
        }
    }

    public interface IBroadcaster
    {
        void BroadcastMessage(string message);
    }

    public interface IMesasgeService
    {
        void DoSomething(Action<IBroadcaster> action);
    }

    [TestFixture]
    public class ThingTest
    {
        private Thing _testObject;
        private IMesasgeService _messageService;
        private IBroadcaster _broadcaster;

        [SetUp]
        public void Setup()
        {
            _messageService = MockRepository.GenerateStub<IMesasgeService>();
            _broadcaster = MockRepository.GenerateMock<IBroadcaster>();
            _testObject = new Thing(_messageService);
        }

        [Test]
        public void TestThisThing()
        {
            _messageService.Stub(mesasgeService => 
                mesasgeService.DoSomething(Arg<Action<IBroadcaster>>.Is.Anything))
                .WhenCalled(method => ((Action<IBroadcaster>) method.Arguments[0])(_broadcaster));

            _testObject.DoIt("Matt");

            _broadcaster.AssertWasCalled(broadcaster => broadcaster.BroadcastMessage("Hello, Matt"));
        }
    }
}