ASP .Net MVC 3:单元测试控制器动作

Question

我是单元测试和模拟概念的新手.我试图弄清楚如何为下面的基本开箱即用用户注册代码编写一个好的测试用例:

[HttpPost]
public ActionResult Register(RegisterModel model)
{
    if (ModelState.IsValid)
    {
        // Attempt to register the user
        MembershipCreateStatus createStatus;
        Membership.CreateUser(model.UserName, model.Password, model.Email, null, null, true, null, out createStatus);

        if (createStatus == MembershipCreateStatus.Success)
        {
            FormsAuthentication.SetAuthCookie(model.UserName, false /* createPersistentCookie */);
            return RedirectToAction("Index", "Home");
        }
        else
        {
            ModelState.AddModelError("", ErrorCodeToString(createStatus));
        }
    }

    // If we got this far, something failed, redisplay form
    return View(model);
}

以下是我需要您的意见/帮助的一些具体要点:

1. 我不一定想在ASP .Net成员资格数据库中创建新用户.
2. 根据传入的模型,如何确保用户成功注册或过程中出现错误.

Answer 1

你的代码有问题.你的行动取决于静态方法:Membership.CreateUser.正如您所知,静态方法是用于单元测试的PITA.

因此,您可以通过引入一个抽象级别来削弱耦合:

public interface IMyService
{
    MembershipCreateStatus CreateUser(string username, string password, string email);
}

然后有一些使用当前成员资格提供者的实现:

public class MyService: IMyService
{
    public MembershipCreateStatus CreateUser(string username, string password, string email)
    {
        MembershipCreateStatus status;
            Membership.CreateUser(username, password, email, null, null, true, null, out status);
        return status;
    }
}

最后是控制器:

public class AccountController : Controller
{
    private readonly IMyService _service;
    public AccountController(IMyService service)
    {
        _service = service;
    }

    [HttpPost]
    public ActionResult Register(RegisterModel model)
    {
        if (ModelState.IsValid)
        {
            // Attempt to register the user
            var status = _service.CreateUser(model.UserName, model.Password, model.Email);
            if (status == MembershipCreateStatus.Success)
            {
                FormsAuthentication.SetAuthCookie(model.UserName, false /* createPersistentCookie */);
                return RedirectToAction("Index", "Home");
            }
            else
            {
                ModelState.AddModelError("", ErrorCodeToString(createStatus));
            }
        }

        // If we got this far, something failed, redisplay form
        return View(model);
    }
}

好了,既然我们已经削弱了耦合,我们就可以使用模拟框架在单元测试中模拟服务并使其变得微不足道.

例如,使用Rhino Mocks,您可以创建以下测试来涵盖2个失败案例:

[TestMethod]
public void Register_Action_Should_Redisplay_View_If_Model_Is_Invalid()    
{
    // arrange
    var sut = new AccountController(null);
    var model = new RegisterModel();
    sut.ModelState.AddModelError("", "invalid email");

    // act
    var actual = sut.Register(model);

    // assert
    Assert.IsInstanceOfType(actual, typeof(ViewResult));
    var viewResult = actual as ViewResult;
    Assert.AreEqual(model, viewResult.Model);
}

[TestMethod]
public void Register_Action_Should_Redisplay_View_And_Add_Model_Error_If_Creation_Fails()
{
    // arrange
    var service = MockRepository.GenerateStub<IMyService>();
    service
        .Stub(x => x.CreateUser(null, null, null))
        .IgnoreArguments()
        .Return(MembershipCreateStatus.InvalidEmail);
    var sut = new AccountController(service);
    var model = new RegisterModel();

    // act
    var actual = sut.Register(model);

    // assert
    Assert.IsInstanceOfType(actual, typeof(ViewResult));
    var viewResult = actual as ViewResult;
    Assert.AreEqual(model, viewResult.Model);
    Assert.IsFalse(sut.ModelState.IsValid);
}

最后的测试是成功案例.我们仍有问题.问题是以下行:

FormsAuthentication.SetAuthCookie(model.UserName, false);

这是什么？这是一个静态方法调用.因此,我们采用与成员资格提供程序相同的方式来削弱控制器和表单身份验证系统的耦合.