Anuraj

Creating Unit Tests for ASP.NET MVC 6 Applications

December 22, 2014 by Anuraj

.Net ASP.Net ASP.Net MVC CodeProject EF Code First Entity Framework

This post is about unit testing ASP.NET MVC 6 applications. Unlike MS Test, this post is using XUnit Framework, which is the currently used unit testing framework for ASP.NET 5 applications.

Similar to TestMethod, XUnit uses Fact / Theory attributes. You can find more comparison details here.

Unit testing class libraries

Here is the unit tests for calculator class, with Add method.

public class CalculatorTests
{
	[Fact]
	public void AddTest()
	{
		var number1 = 10;
		var number2 = 20;
		var expected = 30;

		Calculator calculator = new Calculator();
		var result = calculator.Add(number1, number2);

		Assert.Equal(expected, result);
	}
	
	[Theory]
	[InlineData(10, 10,20)]
	[InlineData(20, 20,40)]
	public void AddTest(int number1, int number2, int expected)
	{
		Calculator calculator = new Calculator();
		var result = calculator.Add(number1, number2);
		
		Assert.Equal(expected, result);
	}
}

And here is source code

public class Calculator
{
	public int Add(int number1, int number2)
	{
		return number1 + number2;
	}
}

Similar to ASP.NET 5 applications, unit test project also requires a project.json file.

{
    "dependencies": {
        "xunit.runner.kre": "1.0.0-*"
    },
    "frameworks": {
        "aspnet50": { },
        "aspnetcore50": { }
    },
    "commands": {
        "test": "xunit.runner.kre"
    }
}

You need to execute the kpm restore command to download the XUnit runner, once it is finished, you can execute k test command to execute the tests. XUnit test runner will display result like this.

XUnit Test Results

If you looked into the XUnit test results you can see something like Total :3, it because of the Theory and InlineData attributes, XUnit will treat the test method as a different one.

Unit testing MVC Controllers

Unlike class libraries, MVC controllers are little difficult to unit test. As controllers contains business logic and database interactions, you need to decouple it and inject it. This project is an ASP.NET MVC 6 project, code is generated using ASP.NET Scaffolding, it uses Entity Framework 7.0 and SQL Server localDb for database operations. In solution I wrote code to decouple the database interaction using repository pattern.

Here is the controller class.

public class EmployeeController : Controller
{
	private IEmployeeRepository _employeeRepository;
	public EmployeeController(IEmployeeRepository employeeRepository)
	{
		_employeeRepository = employeeRepository;
	}
}

I am using ASP.NET dependency injection framework for injecting the repository class to the controller. You can find more details about ASP.NET dependency injection here

public void Configure(IApplicationBuilder app)
{
    app.UseErrorPage();
    app.UseServices(services =>
    {
        services.AddMvc();
        services.AddScoped<IEmployeeRepository, EmployeeRepository>();
    });
 
    app.UseMvc();
}

And here is my index method, which returns employees from the database using repository.

// GET: Employee
public IActionResult Index()
{
	return View(_employeeRepository.FindAll().ToList());
}

And here is the unit test for the same. I am using Moq framework for mocking the

[Fact]
public void VerifyIndexDisplaysAllEmployees()
{
	_employeeRepository.Setup(x => x.FindAll()).Returns(new List<Employee>()
	{
		new Employee() { Id = 1, Name = "Employee 1" },
		new Employee() { Id = 2, Name = "Employee 2" },
		new Employee() { Id = 3, Name = "Employee 3" }
	});

	var indexResult = _employeeController.Index() as ViewResult;

	Assert.NotNull(indexResult);
	var employees = indexResult.ViewData.Model as List<Employee>;
	Assert.Equal(3, employees.Count);
	Assert.Equal(1, employees[0].Id);
	Assert.Equal("Employee 3", employees[2].Name);
}

As XUnit doesn’t have equivalents for Test Initialize / Class Initialize / Setup / Teardown, I have wrote the code to setup the controller and mocks in the test class constructor.

private EmployeeController _employeeController;
private Mock<IEmployeeRepository> _employeeRepository;
public EmployeeControllerTests()
{
	_employeeRepository = new Mock<IEmployeeRepository>();
	_employeeController = new EmployeeController(_employeeRepository.Object);
	var mockModelMetadataProvider = new Mock<IModelMetadataProvider>();
	var viewDataDictionary = new ViewDataDictionary<object>(mockModelMetadataProvider.Object);
	_employeeController.ViewData = viewDataDictionary;
}

As part of Index action, we are returning model object(Employee list), if we didn’t set ViewData property, tests will fail, with Null reference exception. This is because the controller class internally uses the ViewData property to return the Model to the view, while running controller from Unit test context, ASP.NET runtime won’t inject the required services to the view data property, so you need to set it manually.

Here is the Details action.

// GET: Employee/Details/5
public IActionResult Details(System.Int32? id)
{
	if (id == null)
	{
		return new HttpStatusCodeResult(404);
	}

	Employee employee = _employeeRepository.Get(id);
	if (employee == null)
	{
		return new HttpStatusCodeResult(404);
	}

	return View(employee);
}

And here is the unit tests for the same.

[Fact]
public void VerifyDetailsReturns404IfEmployeeIdIsNull()
{
	_employeeRepository
		.Setup(x => x.Get(It.IsAny<int?>())).Returns<Employee>(null);

	var httpStatusCodeResult 
		= _employeeController.Details(null) as HttpStatusCodeResult;

	Assert.NotNull(httpStatusCodeResult);
	Assert.Equal(404, httpStatusCodeResult.StatusCode);
}

[Fact]
public void VerifyDetailsReturns404IfEmployeeNotFound()
{
	_employeeRepository
		.Setup(x => x.Get(It.IsAny<int?>())).Returns<Employee>(null);

	var httpStatusCodeResult 
		= _employeeController.Details(1) as HttpStatusCodeResult;

	Assert.NotNull(httpStatusCodeResult);
	Assert.Equal(404, httpStatusCodeResult.StatusCode);
}

[Fact]
public void VerifyDetailsReturnsEmployee()
{
	_employeeRepository.Setup(x => x.Get(It.IsAny<int?>())).
		Returns((int id) => new Employee() { Id = id, Name = "Employee " + id });

	var viewResult = _employeeController.Details(1) as ViewResult;

	Assert.NotNull(viewResult);
	var employee = viewResult.ViewData.Model as Employee;
	Assert.NotNull(employee);
	Assert.Equal(1, employee.Id);
}

Most of the above tests are pretty straight forward, you can understand pretty easily. Here is the create action method.

[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create(Employee employee)
{
	if (ModelState.IsValid)
	{
		_employeeRepository.Save(employee);
		return RedirectToAction("Index");
	}

	return View("Create", employee);
}

And unit tests for the Create method. One problem with the create method is that, it is using ModelState property of controller class to validate the model. As the model class is using Data Annotations API for validating the model, it is very difficult to mock. So we need to use the actual property to mock validation errors.

[Fact]
public void VerifyCreateEmployeeRedirectsToError()
{
	_employeeRepository.Setup(x => x.Save(It.IsAny<Employee>()));
	var employee = new Employee() { Id = 1 };
	//Mocking the _employeeController.ModelState.IsValid = false
	_employeeController.ModelState.AddModelError("Error", "Name is Required");

	var createResult = _employeeController.Create(employee) as ViewResult;

	Assert.NotNull(createResult);
	Assert.Equal("Create", createResult.ViewName);
}

[Fact]
public void VerifyCreateEmployeeInsertData()
{
	_employeeRepository.Setup(x => x.Save(It.IsAny<Employee>())).Verifiable();
	var employee = new Employee() { 
		Id = 1, 
		Name = "Employee", 
		Designation = "Designation", 
		JoiningDate = DateTime.Now };

	var createResult = _employeeController.Create(employee) as RedirectToActionResult;
	Assert.NotNull(createResult);
	Assert.Equal("Index", createResult.ActionName);
	_employeeRepository.Verify();
}

This code

_employeeController.ModelState.AddModelError("Error", "Name is Required");

is used to mock the model validation error. XUnit running on the tests

XUnit MVC Test Results.

Here is my model class.

public class Employee
{
	public int Id { get; set; }
	[Required]
	public string Name { get; set; }
	[Required]
	public string Designation { get; set; }
	[Required]
	public DateTime JoiningDate { get; set; }
	public string Remarks { get; set; }
}

Repository interface

public interface IEmployeeRepository
{
	Employee Get(int? id);
	void Save(Employee employee);
	void Delete(Employee employee);
	void Update(Employee employee);
	IEnumerable<Employee> FindAll();
}

And the project.json file.

{
  "dependencies": {
    "Kestrel": "1.0.0-beta1",
    "Microsoft.AspNet.Diagnostics": "1.0.0-beta1",
    "Microsoft.AspNet.Hosting": "1.0.0-beta1",
    "Microsoft.AspNet.Mvc": "6.0.0-beta1",
    "Microsoft.AspNet.Server.WebListener": "1.0.0-beta1",
    "Microsoft.Framework.CodeGenerators.Mvc": "1.0.0-*",
    "EntityFramework.SqlServer": "7.0.0-*",
    "Microsoft.AspNet.StaticFiles": "1.0.0-*",
	"xunit.runner.kre": "1.0.0-*",
	"Moq":"1.0.0-*"
  },
  "commands": {
    "web": "Microsoft.AspNet.Hosting --server Microsoft.AspNet.Server.WebListener --server.urls http://localhost:5001",
    "gen": "Microsoft.Framework.CodeGeneration",
	"test": "xunit.runner.kre"
  },
  "frameworks": {
    "aspnet50": {}
  }
}

You can find the source code here

Happy Unit Testing :)

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