CODEWITHSUNDEEP
c#asp.net-mvcunit-testing
mandreko
mandreko

Reputation: 1796

Basic MVC3 UnitTest fails to UpdateModel()

It's been a while since I did any MVC work, so I'm hopefully missing something. I'm trying to write a test and controller action to simply Edit a DTO named "Business".

Controller Action:

[HttpPost]
public ActionResult Edit(string id, Business business)
{
    try
    {
        var model = _businessRepository.Get(id);

        if (model != null)
        {
            UpdateModel(model);

            if (ModelState.IsValid)
            {
                _businessRepository.Save(model);
            }
            else
            {
                return View(business);
            }
        }

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

Test:

[TestMethod]
public void Edit_Post_Action_Updates_Model_And_Redirects()
{
    // Arrange
    var mockBusinessRepository = new Mock<IBusinessRepository>();
    var model = new Business { Id = "1", Name = "Test" };
    var expected = new Business { Id = "1", Name = "Not Test" };

    // Set up result for business repository
    mockBusinessRepository.Setup(m => m.Get(model.Id)).Returns(model);
    mockBusinessRepository.Setup(m => m.Save(expected)).Returns(expected);
    var businessController = new BusinessController(mockBusinessRepository.Object);

    // Act
    var result = businessController.Edit(model.Id, expected) as RedirectToRouteResult;

    // Assert
    Assert.IsNotNull(result);
    Assert.AreEqual(result.RouteValues["action"], "Index");
    mockBusinessRepository.VerifyAll();
}

The line that it is giving an exception on, is the UpdateModel() in the controller. The exception details are:

"Value cannot be null. Parameter name: controllerContext"

Upvotes: 0

Views: 974

Answers (5)

Will Appleby
Will Appleby

Reputation: 486

I had the same problem and used the stack trace to pin this down to the ValueProvider. Building on Andrew's answer above for mocking some of the underlying objects used by a controller, I managed to solve the null value exception by also mocking the ValueProvider like this:

var controller = new MyController();

// ... Other code to mock objects used by controller ...

var mockValueProvider = new Mock<IValueProvider>();
controller.ValueProvider = mockValueProvider.Object;

// ... rest of unit test code which relies on UpdateModel(...)

Upvotes: 0

Andrew
Andrew

Reputation: 5430

Setup the Controller context

The following is code snippet from a project which I work on, so maybe it's to much for you

public class TestBase
    {
        internal Mock<HttpContextBase> Context;
        internal Mock<HttpRequestBase> Request;
        internal Mock<HttpResponseBase> Response;
        internal Mock<HttpSessionStateBase> Session;
        internal Mock<HttpServerUtilityBase> Server;
        internal GenericPrincipal User;

            public void SetContext(Controller controller)
            {
              Context = new Mock<HttpContextBase>();
              Request = new Mock<HttpRequestBase>();
              Response = new Mock<HttpResponseBase>();
              Session = new Mock<HttpSessionStateBase>();
              Server = new Mock<HttpServerUtilityBase>();
       User = new GenericPrincipal(new GenericIdentity("test"), new string[0]);

              Context.Setup(ctx => ctx.Request).Returns(Request.Object);
              Context.Setup(ctx => ctx.Response).Returns(Response.Object);
              Context.Setup(ctx => ctx.Session).Returns(Session.Object);
              Context.Setup(ctx => ctx.Server).Returns(Server.Object);
              Context.Setup(ctx => ctx.User).Returns(User);

              Request.Setup(r => r.Cookies).Returns(new HttpCookieCollection());
              Request.Setup(r => r.Form).Returns(new NameValueCollection());
      Request.Setup(q => q.QueryString).Returns(new NameValueCollection());
              Response.Setup(r => r.Cookies).Returns(new HttpCookieCollection());

              var rctx = new RequestContext(Context.Object, new RouteData());
controller.ControllerContext = new ControllerContext(rctx, controller);
            }
}

Then in your tests you can arrange: 

//Arrange
SetContext(_controller);
Context.Setup(ctx => ctx.Request).Returns(Request.Object);

If you want to test your method with ModelState errors, add:

_controller.ModelState.AddModelError("Name", "ErrorMessage");

Upvotes: 1

mandreko
mandreko

Reputation: 1796

I've managed to get what I wanted working by using Automapper instead of the UpdateModel.

I added in my automapper initialization (IPersistable is an interface for all my DTOs):

Mapper.CreateMap<IPersistable, IPersistable>().ForMember(dto => dto.Id, opt => opt.Ignore());

I then changed my controller action to:

[HttpPost]
public ActionResult Edit(string id, Business business)
{
    try
    {
        var model = _businessRepository.Get(id);

        if (model != null)
        {
            Mapper.Map(business, model);

            if (ModelState.IsValid)
            {
                _businessRepository.Save(model);
            }
            else
            {
                return View(business);
            }
        }

        return RedirectToAction("Index");
    }
    catch
    {
        return View();
    }
}

And changed my test to:

[TestMethod]
public void Edit_Post_Action_Updates_Model_And_Redirects()
{
    // Arrange
    var mockBusinessRepository = new Mock<IBusinessRepository>();
    var fromDB = new Business { Id = "1", Name = "Test" };
    var expected = new Business { Id = "1", Name = "Not Test" };

    // Set up result for business repository
    mockBusinessRepository.Setup(m => m.Get(fromDB.Id)).Returns(fromDB);
    mockBusinessRepository.Setup(m => m.Save(It.IsAny<Business>())).Returns(expected);
    var businessController = new BusinessController(mockBusinessRepository.Object) {ControllerContext = new ControllerContext()};

    //Act
    var result = businessController.Edit(fromDB.Id, expected) as RedirectToRouteResult;

    // Assert
    Assert.IsNotNull(result);
    Assert.AreEqual(result.RouteValues["action"], "Index");
    mockBusinessRepository.VerifyAll();
}

Upvotes: 0

CodingWithSpike
CodingWithSpike

Reputation: 43718

I have some code on Gist that I typically use to set up that ControllerContext. The code is a modified version that was originally taken from Hanselman's blog.

https://gist.github.com/1578697 (MvcMockHelpers.cs)

Upvotes: 1

Martin
Martin

Reputation: 11041

You need to mock the ControllerContext for your BusinessController.

See this question or this one.

Upvotes: 0

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