1. One of the key benefits of ASP.NET MVC is that it facilitates unit testing, allowing you to unit test your controllers and models.
   
2. To start we need to Tool up, there are many testing frameworks to choose from.
   • Microsoft Test – supported directly in visual studio as seen in the previous tutorial.
   • NUnit – Widely used in industry, Download from https://nunit.org/ or install from products folder in solution.
   • Well also use a mocking framework, Download from https://code.google.com/p/moq/ or found in the products folder in the solution. This will generate a “mock” version of a class, based on an interface.
3. To understand TDD we need to go through the process, Hence we are going to use an initial version of the FilmsRUsOnline application to implement pagination using TDD to get us there. The application can be found in the solution folder.

 

4. Unit tests are typically housed in a separate project:
   • To do this we are going to create a class library project.
   • Select the solution FilmsRUsOnline.
   • Right click and select Add new project.
   • Navigate to Visual C# on the left hand tab menu.
   • Select Class Library and call it UnitTests.

   

5. We now need to add the references for Moq and NUnit in are UnitTests Reference folder.
   • This can be done for NUnit once its installed, by selecting reference.
   • Right clicking reference, going to the assemblies and finding the assembly named nunit.framework.
   • For Moq you need to do as above but instead go to browse and open the dialog and search for where you saved the Moq folder and choose Moq.ddl.
   • Also add to references Domain, FilmsRUsOnline and System.Web.Mvc.
6. Add new class to the project UnitTests called UnitTestUtils. This will contain a helper method to encapsulate an “equality assertion” and will contain a helper method to create a mock repository.
   
using Domain.Repositories;
using Domain.Entities;
using NUnit.Framework;
using Moq;
namespace UnitTests
{
 public static class UnitTestUtils
 {
  public static void AssertEqual<T>(this T value, T expected)
  {
   Assert.AreEqual(value, expected);
  }
  public static IFilmsRepository MockFilmsRepository(params Film[] films)
  {
   // Generate an implementer of IFilmsRepository at runtime using Moq.
   var mockProductsRepos = new Mock<IFilmsRepository>();
   mockProductsRepos.Setup(x => x.Films).Returns(films);
   return mockProductsRepos.Object;
  }
 }
}

7. View code file.

 

8. To define unit tests:
   • Define a class and annotate it with [TestFixture].
   • For each test case, write a method and annotate with [Test].
   • Try and follow the naming convention for your test cases SUTName_WhatAmITesting_ExpectedOutcome.
   • Create a class called FilmUnitTests in the UnitTests project.

   
[TestFixture]
public class FilmUnitTests
{
 [Test]
 public void Film_RequestPage_ReturnsPageOfFilms()
 {
  // Add code here, to test whether we can view one page of films.
  // See next codebox for all code
 }


9. In this class called FilmUnitTests use this code:
   
using Domain.Repositories;
using Domain.Entities;
using FilmsRUsOnline.Controllers;
using NUnit.Framework;
namespace UnitTests
{
 [TestFixture]
 public class FilmUnitTests
 {
  [Test]
  public void Film_RequestPage_ReturnsPageOfFilms()
  {
   // Arrange: If there are 5 films in the repository...
   IFilmsRepository repository = UnitTestUtils.MockFilmsRepository(
     new Film { Title="Airplane", Blurb="Classic spoof airline disaster movie", Genre="Comedy", RentalPrice=1.50m },
     new Film { Title="Jaws", Blurb="Shark-fest film that spooked a generation", Genre="Thriller", RentalPrice=1.99m },
     new Film { Title="Love Actually", Blurb="Feel-good family entertainment", Genre="RomCom", RentalPrice=2.99m },
     new Film { Title="Apollo 13", Blurb="Real-life space drama", Genre="Entertainment", RentalPrice=2.99m },
     new Film { Title="Dr. No", Blurb="First appearance for Bond, James Bond", Genre="Entertainment", RentalPrice=1.50m }
   );
   // Create
   var controller = new FilmsController(repository);
   controller.PageSize = 3;
   // Act: ... then when the user asks for the second page (PageSize=3)...
   var result = controller.List(2);
   // Assert: ... they'll just see the last two films.
   var displayedFilms = (IList)result.ViewData.Model;
   displayedFilms.Count.AssertEqual(2);
   displayedFilms[0].Title.AssertEqual("Apollo 13");
   displayedFilms[1].Title.AssertEqual("Dr. No");
  }
 }
}

10. View code file.



11. The code has errors and won’t compile as expected. This is the idea with TDD, so now we enhance the controller so its compatible with the unit test.
    
public class FilmsController : Controller
{
 public int PageSize = 3;
 ...
 public ViewResult List(int pageNumber = 1)
 {
  return View(filmsRepository.Films);
 }
}

12. View code file.

 

13. To run NUnit test:
    • Run NUnit from the Windows Start Menu.
    • in NUnit GUI, Open your UNitTests.dll assembly.
    • Click run and behold the red bar.



14. The controller must be enhanced so that it supports the notion of paging.
    
public class FilmsController : Controller
{
 public int PageSize = 3;
 ...
 public ViewResult List(int pageNumber = 1)
 {
  return View(filmsRepository.Films
     .Skip((pageNumber - 1) * PageSize)
     .Take(PageSize)
     .ToList());
 }
}

15. View code file.

 

16. Now run the unit tests again and behold the green bar.



17. You can now change the page number to view films by typing in the URL after the / “?pageNumber=1“.

We will explore in the next tutorial view techniques, in which we will be able to display the films over multiple pages.