Question

I have a model which contains a link to sql query that fetches information from my db then I loop it out in my view which renders a partial with the resultset in a table. Quite simple and straightforward. Although as I’m really struggling to get better at doing TDD I want to have a test for this. Bare in mind that if you find a test that forces me to rethink my design that’s just fine. Tests should help you see flaws in your designpatterns. I will post some of the code below of my model, and partial:

public class ApplicationModel
{
    public static DeployEntities DeployEntities = new DeployEntities();

    public static IQueryable<Application> GetApplicationList()
    {
        var applications = DeployEntities.Applications.OrderByDescending(a => a.Name);
        return applications.AsQueryable<Application>().Distinct();
    }
}


@{  
  foreach (var a in Deploy.Models.ApplicationModel.GetApplicationList())
                    {      
                <tr id="applications">
                    <td class="row-heading">
                        <p class="pseudo">@a.Name</p>  
                    </td> 
                    <td class="insert-col">
                    <div class="number-insert">
                        <p>Deploy Number</p>
                        <span class="count"></span>
                    </div>

So any thoughts on how I could go about with a test for this. I’m using MVC3 as you can see from the Razor syntax, and Entity Framework. Thanks in advance.

Answer 1

Although as I’m really struggling to get better at doing TDD I want to have a test for this.

The following line ruins your model:

public static DeployEntities DeployEntities = new DeployEntities();

A static hardcoded dependency => impossible to unit test your model in isolation.

In order to weaken the coupling between your DAL and model you could introduce an abstraction:

public interface IApplicationRepository
{
    IQueryable<Application> GetApplications();
}

and then your model could use constructor injection:

public class ApplicationModel
{
    private readonly IApplicationRepository _repository;
    public ApplicationModel(IApplicationRepository repository)
    {
        _repository = repository;
    }

    public static IQueryable<Application> GetApplicationList()
    {
        var applications = _repository.OrderByDescending(a => a.Name);
        return applications.AsQueryable<Application>().Distinct();
    }
}

Now in a unit test you could use a mocking framework such as Rhino Mocks or Moq to mock this repository and set expectations on it and be able to unit test the GetApplicationList method in isolation.