Testing an Edit view with MVCContrib Test Helper - asp.net-mvc

Question

I am using ASP.NET MVC 3, MVCContrib, NUnit and Rhino Mocks. I have posted this but could not get an answer. People are focusing more on my coding that helping me get a decent answer to get this test to pass.
I am trying to test my Edit view. I'm not sure how to code the test for the view. It is a strongly typed view of type NewsEditViewData.
When the view loads, it gets a news item's data by ID from the news service. So in my test I created a stub of the news service:
var id = 1;
var news = new News();
newsServiceStub
.Stub(x => x.FindById(id))
.Return(news);
Now I need to map this news item to NewsEditViewData. I have a mapper (AutoMapper) that does this for me, and in my test I did the following:
newsMapperStub
.Stub(x => x.Map(news, typeof(News), typeof(NewsEditViewData)))
.Return(newsEditViewData);
I'm not sure if I am on the right track so far?
Then I have the following piece of code:
// Act
var actual = sut.Edit(id);
Don't work from my code, I want an answer following best practices. So what all do I need to check for in my assert part? Do I need to also check that a record was returned? I was thinking in the lines of something like:
actual
.AssertViewRendered()
.WithViewData<NewsEditViewData>()
.ShouldBe(newsEditViewData);
This fails. Can someone please help me rewrite this test so that it passes. I want it to check all that needs to be checked.
Here is the full test:
[Test]
public void Edit_should_render_Edit_view()
{
// Arrange
var id = 1;
var news = new News();
var newsEditViewData = new NewsEditViewData();
newsServiceStub
.Stub(x => x.FindById(id))
.Return(news);
newsMapperStub
.Stub(x => x.Map(news, typeof(News), typeof(NewsEditViewData)))
.Return(newsEditViewData);
// Act
var actual = sut.Edit(id);
// Assert
actual
.AssertViewRendered()
.WithViewData<NewsEditViewData>()
.ShouldBe(newsEditViewData);
}
UPDATE 2011-02-14:
In my NewsController I have the following:
private INewsService newsService;
private IMapper newsMapper;
public NewsController(INewsService newsService)
{
Check.Argument.IsNotNull(newsService, "newsService");
this.newsService = newsService;
newsMapper = new NewsMapper(); // TODO: Use dependency injection
}
The action method looks like this:
public ActionResult Edit(int id)
{
Check.Argument.IsNotZeroOrNegative(id, "id");
var news = newsService.FindById(id);
var newsEditViewData = (NewsEditViewData)newsMapper.Map(news, typeof(News), typeof(NewsEditViewData));
return View(newsEditViewData);
}
The error that I am getting in NUnit is:
MyProject.Web.UnitTests.Controllers.NewsControllerTests.Edit_RenderView_EditView:
MvcContrib.TestHelper.AssertionException : was MyProject.Web.Common.ViewData.NewsEditViewData but expected MyProject.Web.Common.ViewData.NewsEditViewData

Answer 1

You haven't shown none of your controller, repository, models. It's a question that is close to impossible to answer without this information. So lets start guessing. You have a model and a view model:
public class News { }
public class NewsEditViewData { }
I am leaving them without any properties for the purpose of this post. Then you probably have a service which is responsible for retrieving and saving your model (the view model should never appear as in/out argument of your service layer). The service should never know about the view model:
public interface INewsService
{
News FindById(int id);
void CreateNews(News news);
}
Then you probably have a mapper:
public interface IMapper
{
object Map(object source, Type sourceType, Type destinationType);
}
And finally I suppose that you have a controller that you are trying to test:
public class NewsController : Controller
{
private readonly INewsService _newsService;
private readonly IMapper _newsMapper;
public NewsController(INewsService newsService, IMapper newsMapper)
{
_newsService = newsService;
_newsMapper = newsMapper;
}
public ActionResult Edit(int id)
{
// WARNING: Meaningless action ahead as it retrieves some
// model from the service and passes this model to
// the service back again for update. In the meantime
// the model is converted to a view model using a mapper
// and passed to the view. So totally meaningless in a real
// application but let's consider for the purpose of this demonstration
var news = _newsService.FindById(id);
_newsService.CreateNews(news);
var newsEditViewData = (NewsEditViewData)_newsMapper.Map(news, typeof(News), typeof(NewsEditViewData));
return View(newsEditViewData);
}
}
OK, up until here it is you that should have provided this information.
And now I can start answering your question about the unit test which might look like this:
[Test]
public void Edit_should_fetch_news_model_from_service_given_an_id_parameter_create_news_and_pass_a_viewmodel_to_the_view()
{
// arrange
// TODO : move this part in the initialization section
// of your unit test to avoid repeating it on each method
var newsServiceStub = MockRepository.GenerateStub<INewsService>();
var newsMapperStub = MockRepository.GenerateStub<IMapper>();
var sut = new NewsController(newsServiceStub, newsMapperStub);
new TestControllerBuilder().InitializeController(sut);
var news = new News();
var id = 123;
var newsEditViewData = new NewsEditViewData();
newsServiceStub
.Stub(x => x.FindById(id))
.Return(news);
newsMapperStub
.Stub(x => x.Map(news, typeof(News), typeof(NewsEditViewData)))
.Return(newsEditViewData);
// act
var actual = sut.Edit(id);
// assert
actual
.AssertViewRendered()
.WithViewData<NewsEditViewData>()
.ShouldBe(newsEditViewData);
newsServiceStub.AssertWasCalled(x => x.CreateNews(news));
}