Unit testing a controller which inherits from LightSpeedControllerBase

I am currently using LightSpeed 4. I have decided to evaluate it, together with implementing my controllers as subclasses of LightSpeedControllerBase. A very important thing in my evaluation is that I need to be able to properly unit test each controller (as opposed to integration testing). I spent many hours last night trying to figure out how to test my controller properly in isolation, but I kept running into the issue of the UnitOfWork object being NULL and therefore it throws an exception in my test.

My controller looks as follows:

public class ListController : LightSpeedControllerBase<ProductCatalogUnitOfWork>
{
    private readonly LightSpeedContext<ProductCatalogUnitOfWork> _context;

    protected override LightSpeedContext<ProductCatalogUnitOfWork> LightSpeedContext
    {
        get { return _context; }
    }

    public ListController(LightSpeedContext<ProductCatalogUnitOfWork> context)
    {
        _context = context;
    }

    public ActionResult List()
    {
        var vendors = UnitOfWork.Find<Vendor>();   
        var model = vendors.ConvertToGetVendorsModel();
        return View(model);
    }
}

In this context, I am wanting to test the List() method. The test criterion is easy, I need to test whether the Find() method is being called on the UnitOfWork object. As mentioned, in attempting to do this, I am consistently getting a NULL value for UnitOfWork inside my ListController when it is called from my test.

My test code (using NUnit) currently looks as follows (although have attempted any combinations of things, all with no success):

    [Test]
    public void List_should_get_vendors()
    {
        // Arrange
        var context = new LightSpeedContext<ProductCatalogUnitOfWork>();
        var uow = new TestUnitOfWork() { Context = context };
        uow.SetExpectedCollectionResult(CreateVendors());
        var controller = new ListController(context);
        // Act
        var result = controller.List() as ViewResult;
        // Assert
        uow.Received().Find<Vendor>();
    }

The test gets an exception on the first line of the List() method. The message is:

'this.UnitOfWork' threw an exception of type 'System.NullReferenceException'

Help on this will be greatly appreciated as my decision whether to continue using LightSpeed depends on this quite a lot.

Thanks Ozzy

You are going to have trouble performing an isolated test because you are leaning on LightSpeedControllerBase which infers a concrete UnitOfWork type (as exposed through the UnitOfWork property and also relies on you having a LightSpeedContext available to instantiate that UnitOfWork instance) so your UnitOfWork isn't going to be easily substituted for a fake. Using LightSpeedControllerBase kind of shunts you down the path of performing more of an integration test and we would recommend using a transactional style test approach for those (use a TransactionScope and rollback on TearDown).

If you want to seperate this out there are a couple of approaches, however based on how you are currently using the UnitOfWork (you are using the IUnitOfWork methods rather than the LINQ IQueryables) you would probably want to look at shifting away from the LightSpeedControllerBase, setting up an IUnitOfWork property for your UnitOfWork and then inject it using IoC or refer to it via a ServiceLocator - be mindful of request scoping in which ever approach you end up taking. This will then allow you to apply a mock/fake for testing.

Jeremy

Also if you end up going down the IUnitOfWork path, you can look at using our TestUnitOfWork which has been provided for this type of situation. More details are in the documentation here: http://www.mindscapehq.com/documentation/lightspeed/Testing-and-Debugging/Unit-Testing

Jeremy