A way to get a HttpContext that is able to be mocked out via HttpContextBase

HttpContextFactory.cs

  public class HttpContextFactory
    {
        private static HttpContextBase context;
        public HttpContextFactory() {}

        public void setHttpContext(HttpContextBase c)
        {
            context = c;
        }

        public HttpContextBase getContext()
        {
            if (context == null)
            {
                return new HttpContextWrapper(HttpContext.Current);
            }
            return context;
        }
    }

In your app you use like: var context = new HttpContextFactory().getContext();
In your tests (using Moq) you use like:
var request = new Mock();
mockContext.SetupGet(c => c.Request).Returns(request.Object);