如何在ShoppingCart控制器/模型中模拟HttpContext

在基于音乐商店教程的实体框架4.0的MVC4应用程序中，我们使用Moq模拟DbContext和单元测试是逻辑。但我们的一种方法很难测试，因为它使用了HttpContext或HttpContextBase。一个示例方法如下：

public static ShoppingCart GetCart(HttpContextBase context)
    {
        var cart = new ShoppingCart();
        cart.ShoppingCartId = cart.GetCartId(context);
        return cart;
    }

从HttpContextBase收集的唯一属性是[CartSessionKey]，如下所示：

public string GetCartId(HttpContextBase context)
{
    if (context.Session[CartSessionKey] == null)
    {
        if (!string.IsNullOrWhiteSpace(context.User.Identity.Name))
        {
            context.Session[CartSessionKey] =
                context.User.Identity.Name;
        }
        else
        {
            // Generate a new random GUID using System.Guid class
            Guid tempCartId = Guid.NewGuid();
            // Send tempCartId back to client as a cookie
            context.Session[CartSessionKey] = tempCartId.ToString();
        }
    }
    return context.Session[CartSessionKey].ToString();
}

我们听说过恐怖故事，HttpContext是一个非常复杂的类，如果你把它打印出来，你就有足够的纸绕地球八圈。

尽管如此，我们还是想嘲笑它。问题是如何嘲笑它。我们要模拟的属性是[CartSessionKey]，以及来自上下文的属性contest.User.Identity.Name。

我们怀疑我们需要使用这样的东西：

        var mockData = new Mock<FakeContext>();
        mockData.Setup(m => m.Orders).Returns(memoryOrderItems);
        mockData.Setup(m => m.Carts).Returns(memoryCartItems);
        Mock<HttpContextBase> mockHttpContext = new Mock<HttpContextBase>();
        Mock<HttpRequestBase> mockHttpRequest = new Mock<HttpRequestBase>();
        mockHttpRequest.Setup(x => x.CartSessionKey).Returns(1);
        mockHttpContext.Setup(x => x.Request).Returns(mockHttpRequest.Object);

但我们找不到如何具体实现这一点，因此在使用CCD_ 9或CCD_。

我们希望有人能帮助我们。

/编辑

当我们这样做时：

 var memoryUserItems = new FakeDbSet<User>()
        {
            new User { Email = "test@test.de",
                       FullName = "Test Person",
                       isAvailable = true,
                       Name = "WHat"
            },
            new User { Email = "test2@test.de",
                       FullName = "Test Person 2",
                       isAvailable = true,
                       Name = "WHat 2"
            }
        };
 (...) Other memory...Items

然后这个：

        // Create mock units of work
        var mockData = new Mock<FakeContext>();
        mockData.Setup(m => m.Orders).Returns(memoryOrderItems);
        mockData.Setup(m => m.Carts).Returns(memoryCartItems);
        mockData.Setup(m => m.Users).Returns(memoryUserItems);
        var principalMock = new Mock<IPrincipal>();
        var identityMock = new Mock<IIdentity>();
        var userMock = 
        identityMock.Setup(x => x.Name).Returns("Test!");
        identityMock.Setup(x => x.IsAuthenticated).Returns(true); // optional ;)
        mockData.Setup(x => x.Identity).Returns(identityMock.Object);
        var httpReqBase = new Mock<HttpRequestBase>(); // this is useful if you want to test Ajax request checks or cookies in the controller.
        var httpContextBase = new Mock<HttpContextBase>();
        httpContextBase.Setup(x => x.User).Returns(principalMock.Object);
        httpContextBase.Setup(x => x.Session[It.IsAny<string>()]).Returns(1); //Here is the session indexer. You can swap 'any' string for specific string.
        httpContextBase.Setup(x => x.Request).Returns(httpReqBase.Object);

我们得到的错误是：

错误3"project.Models.FakeContext"不存在不包含"Identity"的定义，也没有扩展方法"Identity"接受类型的第一个参数找不到"project.Models.FakeContext"（是否缺少using指令或程序集参考？）

/edit2

为了更清楚。我测试的实际方法如下：

    public ActionResult Complete(int id)
    {
        // Make sure that user is currentuser and otherwise bring user to our Thief page
        if (id != db.GetCurrentUserId())
        {
            return View("Thief");
        }
        var cart = ShoppingCart.GetCart(this.HttpContext);
        var currentDate = DateTime.Today;
        var viewModel = new ShoppingCartViewModel
        {
            CartItems = cart.GetCartItems(),
            CartTotal = cart.GetTotal(),
            ProductItems = db.Products.ToList()
        };
        if (viewModel.CartItems.Count() == 0)
        {
            return View("Empty");
        }
        // Try to write cart to order table
        try
        {
            foreach (var item in viewModel.CartItems)
            {
                ProcessOrder(item, id, currentDate);
            }
            // after this we empty the shopping cart
            cart.EmptyCart();
            return View();
        }
        catch
        {
            // Invalid - display error page
            return View("Error");
        }
    }

可以看出，var cart = ShoppingCart.GetCart(this.HttpContext);使用this.HttpContext。在测试中，我只做controller.Complete(1)。我想我无法将新的HttpContext传递给控制器？

/编辑3

在使用下面的代码和mock时，我得到了以下消息：

Test Name:  TestCheckoutCompleteShouldWithEmptyCart
Test FullName:  Controllers.CheckoutControllerTest.TestCheckoutCompleteShouldWithEmptyCart
Test Source:    Controllers'CheckoutControllerTest.cs : line 141
Test Outcome:   Failed
Test Duration:  0:00:00.0158591
Result Message: 
Test method Controllers.CheckoutControllerTest.TestCheckoutCompleteShouldWithEmptyCart threw exception: 
System.NullReferenceException: Object reference not set to an instance of an object.
Result StackTrace:  
at Models'ShoppingCart.cs:line 170
   at 'Models'ShoppingCart.cs:line 20
   at 'Controllers'CheckoutController.cs:line 48
   at Controllers'CheckoutControllerTest.cs:line 143

var principalMock = new Mock<IPrincipal>();
var identityMock = new Mock<IIdentity>();
identityMock.Setup(x => x.Name).Returns("Test!");
identityMock.Setup(x => x.IsAuthenticated).Returns(true); // optional ;)
userMock.Setup(x => x.Identity).Returns(identityMock.Object);
var httpReqBase = new Mock<HttpRequestBase>(); // this is useful if you want to test Ajax request checks or cookies in the controller.
var httpContextBase = new Mock<HttpContextBase>();
httpContextBase.Setup(x => x.User).Returns(principalMock.Object);
httpContextBase.Setup(x => x.Session[It.IsAny<string>()]).Returns(1); //Here is the session indexer. You can swap 'any' string for specific string.
httpContextBase.Setup(x => x.Request).Returns(httpReqBase.Object);

[TestClass]
public class SutTest
{
    [TestMethod]
    public void GetCartId_WhenUserNameIsNotNull_SessionContainsUserName()
    {
        var httpContextStub = new Mock<HttpContextBase>();
        var httpSessionStub = new Mock<ISessionSettings>();
        httpSessionStub.Setup(x => x.Get<string>(It.IsAny<string>())).Returns(() => null);
        httpSessionStub.SetupSequence(x => x.Get<string>(It.IsAny<string>()))
            .Returns(null)
            .Returns("FakeName");
        var httpUserStub = new Mock<IPrincipal>();
        var httpIdenttyStub = new Mock<IIdentity>();
        httpUserStub.SetupGet(x => x.Identity).Returns(httpIdenttyStub.Object);
        httpIdenttyStub.SetupGet(x => x.Name).Returns("FakeName");
        httpContextStub.Setup(x => x.User).Returns(httpUserStub.Object);
        var sut = new Sut(httpSessionStub.Object);
        var result = sut.GetCartId(httpContextStub.Object);
        Assert.AreEqual("FakeName",result );
    }
}

public class SessionSettings : ISessionSettings
{
    private readonly HttpSessionStateBase _session;
    public SessionSettings(HttpSessionStateBase session)
    {
        _session = session;
    }
    public T Get<T>(string key)
    {
        return (T)_session[key];
    }
    public void Set<T>(string key, T value)
    {
        _session[key] = value;
    }
}
public interface ISessionSettings
{
    T Get<T>(string key);
    void Set<T>(string key, T value);
}
public class Sut
{
    private ISessionSettings _sessionSettings;
    public Sut(ISessionSettings sessionSettings)
    {
        _sessionSettings = sessionSettings;
    }
    public string GetCartId(HttpContextBase context)
    {
        if (_sessionSettings.Get<string>(CartSessionKey) == null)
        {
            if (!string.IsNullOrWhiteSpace(context.User.Identity.Name))
            {
                _sessionSettings.Set<string>(CartSessionKey, context.User.Identity.Name);
            }
            else
            {
                // Generate a new random GUID using System.Guid class
                Guid tempCartId = Guid.NewGuid();
                // Send tempCartId back to client as a cookie
                _sessionSettings.Set<string>(CartSessionKey, tempCartId.ToString());
            }
        }
        return _sessionSettings.Get<string>(CartSessionKey);
    }
    private string CartSessionKey = "key";
}