How to unit test this .net MVC function?

I have this function and unit test.

ProfileController Code

[HttpPost]
public ActionResult Edit(int? id)
{
  var redirectUrl = new UrlHelper(Request.RequestContext).Action("Index", "Profile", new { id = 0 });
  return Json(new { Url = redirectUrl });
}

unit test code

[TestMethod]
public void TestDetailsViewData()
{
    var controller = new ProfileController(_Profile); 

    var result = controller.Edit(1) as ViewResult;
    var profile = (VIEWMODELS.Customer.Profile)result.ViewData.Model;
    Assert.AreEqual("Testor", profile.cardName);
}

i would like to test this function and this function will redirect to index page and return ViewPage with data. But the problem is when i run this unit test code i got Null exception at this line ,because of the Request is NULL

var redirectUrl = new UrlHelper(Request.RequestContext).Action("Index", "Profile", new { id = 0 });

so may i know how could i test this?