ASP.NET MVC - Unit testing RenderPartialViewToString() with Moq framework?

Question

I'm using this helper method to turn my PartialViewResult into string and returning it as Json - http://www.atlanticbt.com/blog/asp-net-mvc-using-ajax-json-and-partialviews/

My problem is that I'm using Moq to mock the controller, and whenever I run unit test that uses this RenderPartialViewToString() method, I got the "Object reference not set to an instance of an object." error on ControllerContext.

private ProgramsController GetController()
{
var mockHttpContext = new Mock<ControllerContext>();
mockHttpContext.SetupGet(p => p.HttpContext.User.Identity.Name).Returns("test");
mockHttpContext.SetupGet(p => p.HttpContext.Request.IsAuthenticated).Returns(true);
// Mock Repositories
var mockOrganizationRepository = new MockOrganizationRepository(MockData.MockOrganizationsData());
var mockIRenderPartial = new BaseController();
var controller = new ProgramsController(mockOrganizationRepository, mockIRenderPartial);
controller.ControllerContext = mockHttpContext.Object;
return controller;
}

This returns a proxy controller, and maybe it's the reason why I got that error. Any idea how to unit testing this?

Thank you very much.

Johnsson

Where exactly does the NullReferenceException occur? – Book

It occurs on ControllerContext, I think because of Moq is mocking the controller and only returning the proxy... This is the line: ViewEngineResult viewResult = ViewEngines.Engines.FindPartialView(ControllerContext, viewName); ControllerContext.Controller is null when I hover over it. Thanks, – Johnsson

I'm getting this exception as well, after setting the "controller" and "action" parameters in the RouteData. Full stack trace: pastebin.com/S8c26JLD – Wholewheat

Answer 1

try this:

public static void SetContext(this Controller controller)
        {
            var httpContextBase = new Mock<HttpContextBase>();
            var httpRequestBase = new Mock<HttpRequestBase>();
            var respone = new Mock<HttpResponseBase>();
            var session = new Mock<HttpSessionStateBase>();
            var routes = new RouteCollection();
            RouteConfigurator.RegisterRoutesTo(routes);

            httpContextBase.Setup(x => x.Response).Returns(respone.Object);
            httpContextBase.Setup(x => x.Request).Returns(httpRequestBase.Object);
            httpContextBase.Setup(x => x.Session).Returns(session.Object);
            session.Setup(x => x["somesessionkey"]).Returns("value");
            httpRequestBase.Setup(x => x.Form).Returns(new NameValueCollection());
            controller.ControllerContext = new ControllerContext(httpContextBase.Object, new RouteData(), controller);
            controller.Url = new UrlHelper(new RequestContext(controller.HttpContext, new RouteData()), routes);
        }

Becky

Hi Omu, I'm having this error on this line: ViewEngineResult viewResult = ViewEngines.Engines.FindPartialView(ControllerContext, viewName); The error is "The RouteData must contain an item named 'controller' with a non-empty string value." Thanks. – Johnsson

I tried but no luck, same error :( *** Edited *** How do you manually add a controller variable to the RouteData? – Johnsson

add your stuff between these 2 lines: var routes = new RouteCollection(); RouteConfigurator.RegisterRoutesTo(routes); – Becky

are you using some custom ViewEngine ? – Becky

No, I'm using the MVC ViewEngine, together with the method to renders the view as string. I'm not sure where the problem lies. – Johnsson

You need to mock view engine too. Check this out: #3462506 – Laughingstock