gistfile1.cs

using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;

namespace ConsoleApplication1
{
    [TestClass]
    public class CustomMoq
    {
        public class Message
        {
            public string Body { get; set; }
        }

        public interface IEmailer
        {
            void Send(Message msg);
        }

        public class ThingBeingTested
        {
            private readonly IEmailer _emailer;
            public ThingBeingTested(IEmailer emailer)
            {
                _emailer = emailer;
            }

            public void Method()
            {
                var msg = new Message();
                msg.Body = "The test message";
                _emailer.Send(msg);
            }

        }

        //***Instead of this...
        [TestMethod]
        public void Test()
        {
            var mock = new Mock<IEmailer>();

            mock.Setup(x => x.Send(It.IsAny<Message>()))
                .Callback<Message>(msg =>
                                       {
                                           Assert.IsTrue(msg.Body.Contains("test"));
                                       });

            var sut = new ThingBeingTested(mock.Object);

            sut.Method();
        }

        //***Do this...
        [TestMethod]
        public void Test2()
        {
            var mock = new Mock<IEmailer>();

            mock.Setup(x => x.Send(BodyContains("test")))
                .Verifiable("Expected the email to contain 'test'.");

            var sut = new ThingBeingTested(mock.Object);

            sut.Method();

            mock.VerifyAll();
        }


        public Message BodyContains(string expectedText)
        {
            return Match.Create<Message>(x => x.Body.Contains(expectedText));
        }

    }
}