我正在寻找一种比上面提到的选项更少侵入性的东西。最后，我提出了一个俗气的解决方案，但它可能会让一些人行动得更快一些。

首先，我创建了一个TestSession类:

class TestSession : ISession
{

    public TestSession()
    {
        Values = new Dictionary<string, byte[]>();
    }

    public string Id
    {
        get
        {
            return "session_id";
        }
    }

    public bool IsAvailable
    {
        get
        {
            return true;
        }
    }

    public IEnumerable<string> Keys
    {
        get { return Values.Keys; }
    }

    public Dictionary<string, byte[]> Values { get; set; }

    public void Clear()
    {
        Values.Clear();
    }

    public Task CommitAsync()
    {
        throw new NotImplementedException();
    }

    public Task LoadAsync()
    {
        throw new NotImplementedException();
    }

    public void Remove(string key)
    {
        Values.Remove(key);
    }

    public void Set(string key, byte[] value)
    {
        if (Values.ContainsKey(key))
        {
            Remove(key);
        }
        Values.Add(key, value);
    }

    public bool TryGetValue(string key, out byte[] value)
    {
        if (Values.ContainsKey(key))
        {
            value = Values[key];
            return true;
        }
        value = new byte[0];
        return false;
    }
}

然后我在控制器的构造函数中添加了一个可选参数。如果该参数存在，则将其用于会话操作。否则，使用HttpContext。会话:

class MyController
{

    private readonly ISession _session;

    public MyController(ISession session = null)
    {
        _session = session;
    }


    public IActionResult Action1()
    {
        Session().SetString("Key", "Value");
        View();
    }

    public IActionResult Action2()
    {
        ViewBag.Key = Session().GetString("Key");
        View();
    }

    private ISession Session()
    {
        return _session ?? HttpContext.Session;
    }
}

现在我可以将我的TestSession注入到控制器中:

class MyControllerTest
{

    private readonly MyController _controller;

    public MyControllerTest()
    {
        var testSession = new TestSession();
        var _controller = new MyController(testSession);
    }
}

我们必须通过使用HttpContextManager来模拟HttpContext，并从我们的应用程序和单元测试中调用工厂

public class HttpContextManager 
{
    private static HttpContextBase m_context;
    public static HttpContextBase Current
    {
        get
        {
            if (m_context != null)
                return m_context;

            if (HttpContext.Current == null)
                throw new InvalidOperationException("HttpContext not available");

            return new HttpContextWrapper(HttpContext.Current);
        }
    }

    public static void SetCurrentContext(HttpContextBase context)
    {
        m_context = context;
    }
}

然后替换所有对HttpContext的调用。当前与HttpContextManager。当前和已获得相同的方法。然后在测试时，您还可以访问HttpContextManager并模拟您的期望

这是一个使用Moq的例子:

private HttpContextBase GetMockedHttpContext()
{
    var context = new Mock<HttpContextBase>();
    var request = new Mock<HttpRequestBase>();
    var response = new Mock<HttpResponseBase>();
    var session = new Mock<HttpSessionStateBase>();
    var server = new Mock<HttpServerUtilityBase>();
    var user = new Mock<IPrincipal>();
    var identity = new Mock<IIdentity>();
    var urlHelper = new Mock<UrlHelper>();

    var routes = new RouteCollection();
    MvcApplication.RegisterRoutes(routes);
    var requestContext = new Mock<RequestContext>();
    requestContext.Setup(x => x.HttpContext).Returns(context.Object);
    context.Setup(ctx => ctx.Request).Returns(request.Object);
    context.Setup(ctx => ctx.Response).Returns(response.Object);
    context.Setup(ctx => ctx.Session).Returns(session.Object);
    context.Setup(ctx => ctx.Server).Returns(server.Object);
    context.Setup(ctx => ctx.User).Returns(user.Object);
    user.Setup(ctx => ctx.Identity).Returns(identity.Object);
    identity.Setup(id => id.IsAuthenticated).Returns(true);
    identity.Setup(id => id.Name).Returns("test");
    request.Setup(req => req.Url).Returns(new Uri("http://www.google.com"));
    request.Setup(req => req.RequestContext).Returns(requestContext.Object);
    requestContext.Setup(x => x.RouteData).Returns(new RouteData());
    request.SetupGet(req => req.Headers).Returns(new NameValueCollection());

    return context.Object;
}

然后在单元测试中使用它，我在Test Init方法中调用它

HttpContextManager.SetCurrentContext(GetMockedHttpContext());

然后，您可以在上面的方法中添加来自Session的预期结果，您希望它可以用于您的web服务。

你可以通过创建一个新的HttpContext来“伪造”它，就像这样:

http://www.necronet.org/archive/2010/07/28/unit-testing-code-that-uses-httpcontext-current-session.aspx

我把这段代码放到一个静态helper类中，如下所示:

public static HttpContext FakeHttpContext()
{
    var httpRequest = new HttpRequest("", "http://example.com/", "");
    var stringWriter = new StringWriter();
    var httpResponse = new HttpResponse(stringWriter);
    var httpContext = new HttpContext(httpRequest, httpResponse);

    var sessionContainer = new HttpSessionStateContainer("id", new SessionStateItemCollection(),
                                            new HttpStaticObjectsCollection(), 10, true,
                                            HttpCookieMode.AutoDetect,
                                            SessionStateMode.InProc, false);

    httpContext.Items["AspSession"] = typeof(HttpSessionState).GetConstructor(
                                BindingFlags.NonPublic | BindingFlags.Instance,
                                null, CallingConventions.Standard,
                                new[] { typeof(HttpSessionStateContainer) },
                                null)
                        .Invoke(new object[] { sessionContainer });

    return httpContext;
}

或者不是使用反射来构造新的httpessionstate实例，你可以将你的httpessionstatecontainer附加到HttpContext(根据Brent M. Spell的评论):

SessionStateUtility.AddHttpSessionStateToContext(httpContext, sessionContainer);

然后你可以像这样在单元测试中调用它:

HttpContext.Current = MockHelper.FakeHttpContext();

如果您正在使用MVC框架，这应该可以工作。我使用Milox的FakeHttpContext并添加了一些额外的代码行。这个想法来自这个帖子:

http://codepaste.net/p269t8

这似乎在MVC 5中工作。我还没有尝试在早期版本的MVC。

HttpContext.Current = MockHttpContext.FakeHttpContext();

var wrapper = new HttpContextWrapper(HttpContext.Current);

MyController controller = new MyController();
controller.ControllerContext = new ControllerContext(wrapper, new RouteData(), controller);

string result = controller.MyMethod();

你可以试试FakeHttpContext:

using (new FakeHttpContext())
{
   HttpContext.Current.Session["CustomerId"] = "customer1";       
}

@Ro Hit给出的答案对我帮助很大，但我缺少用户凭据，因为我必须伪造一个用户进行身份验证单元测试。因此，让我描述一下我是如何解决它的。

根据此，如果添加方法

    // using System.Security.Principal;
    GenericPrincipal FakeUser(string userName)
    {
        var fakeIdentity = new GenericIdentity(userName);
        var principal = new GenericPrincipal(fakeIdentity, null);
        return principal;
    }

然后追加

    HttpContext.Current.User = FakeUser("myDomain\\myUser");

到TestSetup方法的最后一行就完成了，添加用户凭据并准备用于身份验证测试。

我还注意到HttpContext中还有其他你可能需要的部分，比如. mappath()方法。这里有一个可用的FakeHttpContext，它可以通过NuGet安装。