Unit Testing Asp.Net WebApi Controllers

I am trying to unit test an ApiController and set the current HttpContext, but every time I try and set the request information for the controller HttpContext.Current still seems to be null.

Here is the code:

[TestMethod]
public void MakePayment()
{
     var config = new HttpConfiguration();
     var request = new HttpRequestMessage(HttpMethod.Post, "http://localhost/api/payment");
     var route = config.Routes.MapHttpRoute("DefaultApi", "api/{controller}/{id}");
     var routeData = new HttpRouteData(route, new HttpRouteValueDictionary { { "controller", "payment" } });

     var mockUserStore = new Mock<IUserStore<ApplicationUser>>();
     var mockUserManager = new Mock<ApplicationUserManager>(mockUserStore.Object);
     mockUserManager.Setup(x => x.GetUser(It.IsAny<string>())).Returns(new ApplicationUser());

     IPayPalService payPalService = new PayPalService(mockUserManager.Object);

     var paymentController = new PaymentController(payPalService);
     paymentController.ControllerContext = new HttpControllerContext(config, routeData, request);
     paymentController.Request = request;
     paymentController.Request.Properties[HttpPropertyKeys.HttpConfigurationKey] = config;

     Payment payment = paymentController.DepositMoney(50.00);

     Assert.AreEqual(payment.intent, "sale");
}

Is there anything that I am missing here?