c# - 如何使用自定义模型 Binder 对路由进行单元测试

Question

我有一个自定义模型 Binder ，用于检查用户是否有权访问他要求的文档；我想知道如何测试使用此自定义 Binder 的路由？

我尝试进行此测试，但出现此错误:

MvcContrib.TestHelper.AssertionException : Value for parameter 'contract' did not match: expected 'Domain.Models.Contract' but was ''; no value found in the route context action parameter named 'contract' - does your matching route contain a token called 'contract'?

[SetUp]
public void Setup()
{
    MvcApplication.RegisterModelBinders();
    MvcApplication.RegisterRoutes(RouteTable.Routes);
}

[Test]
public void VersionEdit()
{
    var contract = TestHelper.CreateContract();
    var route = "~/Contract/" + contract.Id.ToString() + "/Version/Edit/" + 
        contract.Versions.Count;
    route.ShouldMapTo<VersionController>(c => c.Edit(contract));
}

如果我尝试调试自定义 Binder ，则永远不会被调用。

我的路线定义:

public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                "VersionToken", // Route name
                "Contract/{contractId}/Version/{version}/{action}/{token}", // URL with parameters
                new { controller = "Version", action = "ViewContract", version = 1, token = UrlParameter.Optional } // Parameter defaults
            );

            routes.MapRoute(
                "Version", // Route name
                "Contract/{contractId}/Version/{version}/{action}", // URL with parameters
                new { controller = "Version", action = "Create", version = UrlParameter.Optional } // Parameter defaults
            );

            routes.MapRoute(
                "Default", // Route name
                "{controller}/{action}/{id}", // URL with parameters
                new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
            );

            if (HttpContext.Current != null && !HttpContext.Current.IsDebuggingEnabled) routes.IgnoreRoute("CI");
        }

我的模型 Binder :

public static void RegisterModelBinders()
        {
            var session = (ISession)DependencyResolver.Current.GetService(typeof(ISession));
            var authService = (IAuthenticationService)DependencyResolver.Current.GetService(typeof(IAuthenticationService));
            System.Web.Mvc.ModelBinders.Binders[typeof (Contract)] = new ContractModelBinder(session, authService);
        }

public class ContractModelBinder : DefaultModelBinder
    {
        private readonly ISession _session;
        private readonly IAuthenticationService _authService;
        public ContractModelBinder(ISession session, IAuthenticationService authService)
        {
            _session = session;
            _authService = authService;
        }

        public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
        {
            var contractId = GetValue(bindingContext, "contractId");
            var version = GetA<int>(bindingContext,"version");
            var token = GetValue(bindingContext, "token");

            var contract = _session.Single<Contract>(contractId);
            if (contract == null) 
            {
                throw new HttpException(404, "Not found");
            }
            if (contract.Versions.Count < version.Value)
            {
                throw new HttpException(404, "Not found");
            }
            contract.RequestedVersionNumber = version.Value;
            if(token == null)
            {
                var user = _authService.LoggedUser();
                if (user == null) throw new HttpException(401, "Unauthorized");
                if (contract.CreatedBy == null || !contract.CreatedBy.Id.HasValue || contract.CreatedBy.Id.Value != user.Id)
                {
                    throw new HttpException(403, "Forbidden");
                }
            }
            else
            {
                contract.RequestedToken = token;
                var userToken = contract.RequestedVersion.Tokens.SingleOrDefault(x => x.Token == token);
                if (userToken == null)
                {
                    throw new HttpException(401, "Unauthorized");
                }
            }

            return contract;
        }

        private static T? GetA<T>(ModelBindingContext bindingContext, string key) where T : struct, IComparable
        {
            if (String.IsNullOrEmpty(key)) return null;
            //Try it with the prefix...
            var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName + "." + key);
            //Didn't work? Try without the prefix if needed...
            if (valueResult == null && bindingContext.FallbackToEmptyPrefix)
            {
                valueResult = bindingContext.ValueProvider.GetValue(key);
            }
            if (valueResult == null)
            {
                return null;
            }
            return (T)valueResult.ConvertTo(typeof(T));
        }

        private static string GetValue(ModelBindingContext bindingContext, string key)
        {
            if (String.IsNullOrEmpty(key)) return null;
            //Try it with the prefix...
            var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName + "." + key);
            //Didn't work? Try without the prefix if needed...
            if (valueResult == null && bindingContext.FallbackToEmptyPrefix)
            {
                valueResult = bindingContext.ValueProvider.GetValue(key);
            }
            if (valueResult == null)
            {
                return null;
            }
            return valueResult.AttemptedValue;
        }
    }

Answer 1

当测试路由时，MvcContrib TestHelper 不会调用 MVC 管道和模型绑定(bind)器。模型绑定(bind)器应该单独进行单元测试。绑定(bind)独立于路由，一旦实例化 Controller 并调用操作就会发生。

在这个例子中，你是单元测试路线。因此，您需要确保 ~/Contract/5/Version/Edit/3 正确映射到 VersionController 上的 Edit 操作是这样完成的:

"~/Contract/5/Version/Edit/3".ShouldMapTo<VersionController>(c => c.Edit(null));