gistfile1.txt

public static void SetFakeControllerContext(this Controller controller, NameValueCollection querystring = null)
{
    var context = new Mock<HttpContextBase>();
    context.Setup(c => c.Request.QueryString).Returns(querystring ?? new NameValueCollection());
    controller.ControllerContext = new ControllerContext(context.Object, new RouteData(),
        new Mock<ControllerBase>().Object);