如何对依赖于 HttpContext 的控制器进行单元测试

Question

我想知道当我的控制器从依赖于HttpContext 的基本控制器继承时如何对它进行单元测试。下面是我继承的控制器，名为 BaseInterimController。下面是我希望进行单元测试的AccountController 方法。我们正在使用最小起订量。

public abstract class BaseInterimController : Controller
{

    #region Properties
    protected string InterimName
    {
        get { return MultiInterim.GetInterimName(InterimIdentifier); }
    }

    internal virtual string InterimIdentifier
    {
        get { return System.Web.HttpContext.Current.Request.RequestContext.RouteData.Values["InterimIdentifier"].ToString(); }
    }
}

public class AccountController : BaseInterimController
{
    [HttpPost]
    [AllowAnonymous]
    [ValidateInput(false)]
    [Route(@"{InterimIdentifier:regex([a-z]{7}\d{4})}/Account/Signin")]
    public ActionResult Signin(LoginViewModel model)
    {
        if (ModelState.IsValid)
        {
            var identity = Authentication.SignIn(model.Username,
                model.Password) as LegIdentity;

            if (identity != null && identity.IsAuthenticated)
            {
                return Redirect(model.ReturnUrl);
            }
            else
            {
                // Sign in failed
                ModelState.AddModelError("",
                    Authentication.ExternalSignInFailedMessage);
            }
        }
        return View(model);
    }
}

Answer 1

将您的控制器与HttpContext 耦合可能会使您的代码非常难以测试，因为在单元测试期间HttpContext 为空，除非您尝试模拟它；你真的不应该这样做。不要模拟你不拥有的代码。

尝试将您想要从 HttpContext 获取的功能抽象为您可以控制的东西。

这只是一个例子。如果需要，您可以尝试使其更加通用。我将专注于您的具体情况。

你直接在你的控制器中调用它

System.Web.HttpContext.Current.Request
    .RequestContext.RouteData.Values["InterimIdentifier"].ToString();

当您真正追求的是获得InterimIdentifier 值的能力时。类似的东西

public interface IInterimIdentityProvider {
       string InterimIdentifier { get; }
}

public class ConcreteInterimIdentityProvider : IInterimIdentityProvider {
    public virtual string InterimIdentifier {
        get { return System.Web.HttpContext.Current.Request.RequestContext.RouteData.Values["InterimIdentifier"].ToString(); }
    }
}

稍后可以在具体类中实现并注入到您的控制器中，前提是您使用的是依赖注入。

你的基本控制器看起来像

public abstract class BaseInterimController : Controller {
    protected IInterimIdentityProvider identifier;
    public BaseInterimController(IInterimIdentityProvider identifier) {
        this.identifier = identifier;
    }

    protected string InterimName {
        get { return MultiInterim.GetInterimName(identifier.InterimIdentifier); }
    }

    //This can be refactored to the code above or use what you had before
    //internal virtual string InterimIdentifier {
    //    get { return identifier.InterimIdentifier; }
    //}
}    

public class AccountController : BaseInterimController
{
    public AccountController(IInterimIdentityProvider identifier) 
        : base(identifier){ }

    [HttpPost]
    [AllowAnonymous]
    [ValidateInput(false)]
    [Route(@"{InterimIdentifier:regex([a-z]{7}\d{4})}/Account/Signin")]
    public ActionResult Signin(LoginViewModel model)
    {
        if (ModelState.IsValid)
        {
            var identity = Authentication.SignIn(model.Username,
                model.Password) as LegIdentity;

            if (identity != null && identity.IsAuthenticated)
            {
                return Redirect(model.ReturnUrl);
            }
            else
            {
                // Sign in failed
                ModelState.AddModelError("",
                    Authentication.ExternalSignInFailedMessage);
            }
        }
        return View(model);
    }
}

这允许实现的控制器不依赖于HttpContext，这将允许更好的单元测试，因为您可以使用 Moq 轻松模拟/伪造IInterimIdentityProvider 接口，以便在测试期间返回您想要的内容。

[TestMethod]
public void Account_Controller_Should_Signin() {
    //Arrange
    var mock = new Mock<IInterimIdentityProvider>();
    mock.Setup(m => m.InterimIdentifier).Returns("My identifier string");
    var controller = new AccountController(mock.Object);
    var model = new LoginViewModel() {
        Username = "TestUser",
        Password = ""TestPassword
    };
    //Act
    var actionResult = controller.Signin(model);
    //Assert
    //...assert your expected results
}