Testable, mockable version of a url.content resolver

ContentResolver.cs

using System.Web;
using System.Web.Mvc;

namespace KK.Store.DigitalCoupons.Web.Controllers
{
    public class ContentResolver : IContentResolver
    {
        public string Resolve(string imageLocation, HttpRequestBase httpRequestBase)
        {
            return new UrlHelper(httpRequestBase.RequestContext).Content(imageLocation);
        }
    }
}

ContentResolverTests.cs

using System.Web;
using System.Web.Routing;
using KK.Store.DigitalCoupons.Web.Controllers;
using Moq;
using NUnit.Framework;

namespace KK.Store.DigitalCoupons.Web.Tests.Controllers
{
    public class ContentResolverTests
    {
        [TestFixture]
        public class when_resolving_the_content_images
        {
            [Test]
            public void then_should_resolve_to_proper_location()
            {
                // Arrange
                var resolver = new ContentResolver();

                // Act
                var httpContextBase = new Mock<HttpContextBase>();
                var httpRequestBase = new Mock<HttpRequestBase>();

                httpContextBase.Setup(@base => @base.Request).Returns(httpRequestBase.Object);
                
                httpRequestBase.Setup(@base => @base.ApplicationPath).Returns("/Test");


                var requestContext = new Mock<RequestContext>();
                requestContext.SetupGet(context => context.HttpContext).Returns(httpContextBase.Object);
                
                httpRequestBase.SetupGet(@base => @base.RequestContext).Returns(requestContext.Object);

                var url = resolver.Resolve("~/Content/loading.gif", httpRequestBase.Object);

                // Assert
                Assert.That(url, Is.EqualTo("/Test/Content/loading.gif"));
            }
        } 
    }
}

IContentResolver.cs

using System.Web;

namespace KK.Store.DigitalCoupons.Web.Controllers
{
    public interface IContentResolver
    {
        string Resolve(string imageLocation, HttpRequestBase httpRequestBase);
    }
}