Question

Here’s my scenario:

I’m working with a .NET MVC 4.0 project, with a repository (as you’d expect), and trying to implement the Moq/xUnit testing libraries into a .NET Unit Testing project.

I’ve got this far:

MVC Controller

private IHOLService _service;

public PolicyController(IHOLService service)
{
      _service = service;
}

public ActionResult Index()
{
     var policies = _service.GetAllPolicies(100, 0).ToList();

     return View(policies);
}

Unit testing class

[Fact]
 public void GetPolicies()
 {
            // Arrange
            var mockService = new Mock<IHOLService>();
            List<Policy> policy = new List<Policy>()
            mockService.Setup(cr => cr.GetAllPolicies(10, 0)).Returns(policy);
            var controller = new PolicyController(mockService.Object);

            // policy here contains 0 results.

             // Act
        var result = (ViewResult)controller.Index();

        var model = result.ViewData.Model; // equals 0.

        // Assert
        var listCategories = Assert.IsAssignableFrom<List<Policy>>(result.ViewData.Model);

         // listCategories.Count equals 0 results.

        Assert.Equal(10, listCategories.Count); // Thus always fails
  }

My problem is that when the Controller is called directly, everything works fine, 100 policies are loaded.

However, when I run the test, 0 products are loaded, in which I’m guessing is a problem with the mocking calls somewhere down the line, potentially to do with the service initialisation. Has anyone ever had this before and can offer advice?

Also, am I correct to test my Service, rather than my Repository held at data layer?

Thanks in advance.

Answer 1

In your test code, you initialize policy to an empty list, then tell your mock service to return this empty list. To make the test load policies, you need to put some policy instances into your policy list.

I would write a test which looks something like this:

[Fact]
public void GetPolicies()
{
   // Arrange
   var mockService = new Mock<IHOLService>();
   Policy expectedPolicy = new Policy(); // substitute for the real way you construct these
   List<Policy> policy = new List<Policy>() { expectedPolicy };
   mockService.Setup(cr => cr.GetAllPolicies(10, 0)).Returns(policy);

   // Act
   var result = (ViewResult)controller.Index();

   var model = result.ViewData.Model; // equals 0.

   // Assert
   var listCategories = Assert.IsAssignableFrom<List<Policy>>(result.ViewData.Model);

   Assert.Equal(expectedPolicy, listCategories.First());        
}

But it really depends on what aspect of your code you are trying to unit test. From what I can see, this test simply confirms that you are storing the Policy objects as expected. You might write further tests for any logic that depends on the Policy instances themselves.