ASP.NET MVC Controller post method unit test: ModelState.IsValid always true

Question

I have written my first unit tests for an ASP.NET MVC web application. All works fine and it is giving me valuable information, but I can't test errors in the view model. The ModelState.IsValid is always true, even when some values are not filled in (empty string or null).

I have read already that the model validation happens when the posted data is mapped to the model and you need to write some code to do the model verification yourself:

I have tried the three examples provided in the linked webpages, but it seems not to work for me.

Some code:

My viewmodel

...
[Required(ErrorMessageResourceName = "ErrorFirstName", ErrorMessageResourceType = typeof(Mui))]
[MaxLength(50)]
[Display(Name = "Firstname", ResourceType = typeof(Mui))]
public string FirstName { get; set; }
...

The controller

...
 [HttpPost]
    public ActionResult Index(POSViewModel model)
    {
        Contract contract = contractService.GetContract(model.ContractGuid.Value);

        if (!contract.IsDirectDebit.ToSafe())
        {
            ModelState.Remove("BankName");
            ModelState.Remove("BankAddress");
            ModelState.Remove("BankZip");
            ModelState.Remove("BankCity");
            ModelState.Remove("AccountNr");
        }

        if (ModelState.IsValid)
        {
            ...

            contractValidationService.Create(contractValidation);
            unitOfWork.SaveChanges();

            return RedirectToAction("index","thanks");
        }
        else
        {
            return Index(model.ContractGuid.ToString());
        }
    }

My unit test

  posViewModel.FirstName = null;
  posViewModel.LastName = "";
 ...
 var modelBinder = new ModelBindingContext()
        {
            ModelMetadata = ModelMetadataProviders.Current.GetMetadataForType(() => posViewModel, posViewModel.GetType()),
            ValueProvider = new NameValueCollectionValueProvider(new System.Collections.Specialized.NameValueCollection(), CultureInfo.InvariantCulture)
        };
        var binder = new DefaultModelBinder().BindModel(new ControllerContext(), modelBinder);
        posController.ModelState.Clear();
        posController.ModelState.Merge(modelBinder.ModelState);

        ActionResult result = posController.Index(posViewModel);

        //Assert
        mockContractValidationService.Verify(m => m.Create(It.IsAny<ContractValidation>()), Times.Never);
        Assert.IsInstanceOfType(result, typeof(ViewResult));

On the view, I'm using unobtrusive JavaScript validation, and it works.

Might be of use : http://stackoverflow.com/questions/8165026/testing-modelstate-is-always-valid-in-asp-net-mvc — Jason Evans, Mar 21 '14 at 15:09
@JasonEvans I already tried that, this was the solution Scott Hanselmann provided on the SO link. — CyclingFreak, Mar 21 '14 at 15:17

score 115 · Answer 1 · edited Jun 27 '15 at 16:34

You're trying to test two different things at the same time. The controller is not reponsible for validating the model state, only for behaving differently based on the result of that validation. So your unit tests for the controller shouldn't try to test the validation, that should be done in a different test. In my opinion you should have three unit tests:

One that verifies whether model validation correctly
One that validates whether the controller behaves correctly when modelstate is valid
One that validates whether the controller behaves correctly when modelstate is invalid

Here's how you can do that:

1.Model validation

[Test]
public void test_validation()
{
    var sut = new POSViewModel();
    // Set some properties here
    var context = new ValidationContext(sut, null, null);
    var results = new List<ValidationResult>();
    var isModelStateValid =Validator.TryValidateObject(sut, context, results, true);

    // Assert here
}

2.Controller with invalid modelstate

[Test]
public void test_controller_with_model_error()
{
    var controller = new PosController();
    controller.ModelState.AddModelError("test", "test");

    ActionResult result = posController.Index(new PosViewModel());

    // Assert that the controller executed the right actions when the model is invalid
}

3.Controller with valid modelstate

[Test]
public void test_controller_with_valid_model()
{
    var controller = new PosController();
    controller.ModelState.Clear();

    ActionResult result = posController.Index(new PosViewModel());

    // Assert that the controller executed the right actions when the model is valid
}

Thanks for your effort. But case 1 is still giving me the that ModelState.IsValid = true. Case 2 is working and it is a good idea to seperate things for testing, so that is OK. But still stuck on the original problem. — CyclingFreak, Mar 22 '14 at 12:54
I know it a little old answer, but would it not be testing the framework with the **first** unit test? And therefor not needed? :) — TryingToImprove, Aug 16 '14 at 10:42
No, not really, you'd be testing whether the model has the correct validations set up. Whether you want to test that or not is a different issue, but it's definetely testing your code, not the framework — Kenneth, Aug 16 '14 at 14:23

score 12 · Accepted Answer · edited May 23 '17 at 10:31

I found this solution: SO: Validation does not work when I use Validator.TryValidateObject combined with the solution @Kenneth provided:

[TestMethod]
    public void test_validation()
    {
        var sut = new POSViewModel();
        // Set some properties here
        var context = new ValidationContext(sut, null, null);
        var results = new List<ValidationResult>();
        TypeDescriptor.AddProviderTransparent(new AssociatedMetadataTypeTypeDescriptionProvider(typeof(POSViewModel), typeof(POSViewModel)), typeof(POSViewModel));

        var isModelStateValid = Validator.TryValidateObject(sut, context, results, true);

        // Assert here
    }

If you have a class library with all you resources in, don't forget to reference it in your test project.

What is the Assert? Complete the answer. – Apollo Oct 20 '17 at 14:45 — Apollo, Oct 20 '17 at 14:45
You can assert isModelStateValid and results – Sonya Sep 20 '22 at 22:32 — Sonya, Sep 20 '22 at 22:32

ASP.NET MVC Controller post method unit test: ModelState.IsValid always true

2 Answers2

Linked

Related