[转]模拟HttpContext 实现ASP.NET MVC 的单元测试

• 众所周知 ASP.NET MVC 的一个显著优势即可以很方便的实现单元测试，但在我们测试过程中经常要用到HttpContext，而默认情况下单元测试框架是不提供HttpContext的模拟的，本文通过MOQ框架实现对HttpContext的模拟从而实现更便利的单元测试。

  一、Moq框架使用

  Moq是一个非常优秀的模拟框架，可以实现对接口成员的模拟，常用在TDD中。 可在此处下载http://code.google.com/p/moq/downloads/list 也可以通过Nuget直接下载。

  先来看一个简单的moq应用

  1. 定义一个简单接口且不需要实现接口(Moq就是模拟框架因此不需要实现)

  using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Text;
  
   namespace Stphen.Sample.<a href="http://www.it165.net/pro/webasp/" target="_blank" class="keylink">ASP</a>NETMvc.MockUnitTest.Bussiness
   {
      public interface IFoo
      {
          void DoSomeThing(string thingName);
          bool IsLoveFoo();
  
          string FooName { get; set; }
      }
   }

• 2. 在测试代码中我实现了对接口的Mock

using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
using Stphen.Sample.<a href="http://www.it165.net/pro/webasp/" target="_blank" class="keylink">ASP</a>NETMvc.MockUnitTest.Bussiness;

namespace Stephen.Sample.ASPNETMvc.MockUnitTest.TestProject
{
    [TestClass]
    public class MockUnitTest
    {
        private readonly Mock<IFoo> _fooMock;

        public MockUnitTest()
        {
            _fooMock = new Mock<IFoo>();
        }

        [TestMethod]
        public void MockDoSomeThingMethodTest()
        {
            _fooMock.Setup(foo => foo.DoSomeThing(It.IsAny<string>())).Callback((string s) => Console.WriteLine(s));
            _fooMock.Object.DoSomeThing("HelloWorld");
        }

        [TestMethod]
        public  void MockIsLoveMockFramewrokMethodTest()
        {
            _fooMock.Setup(foo => foo.IsLoveFoo()).Returns(true);
            Assert.AreEqual(true, _fooMock.Object.IsLoveFoo());
        }

        [TestMethod]
        public  void MockFooNamePropertyTest()
        {
            _fooMock.Setup(foo => foo.FooName).Returns("stephen");
            Assert.AreEqual("stephen",_fooMock.Object.FooName);
        }
    }
}

第一个方法没有返回值，第二个有返回值分别用Mock 的 Callback 和 return 方法。

二、通过Moq框架实现HttpContext的模拟（MvcContextMock）

using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Web;
 using System.Web.Routing;
 using System.Web.Mvc;
 using Moq;
 namespace MvcContextMock
 {
     /// <summary>
     /// Mvc Context 工厂
     /// </summary>
     public static class MvcContextMockFactory
     {
         private static ControllerContext controllerContext = null;
         /// <summary>
         /// 创建ControllerContext
         /// </summary>
         /// <param name="controller">Controller</param>
         /// <returns></returns>
         public static ControllerContext CreateControllerContext(Controller controller)
         {
              controllerContext = new ControllerContext
                (
               CreateHttpContext(),
               new RouteData(),
                controller);
             return controllerContext;
         }

         /// <summary>
         /// 创建ControllerContext
         /// </summary>
         /// <param name="controller">Controller</param>
         /// <param name="contextBase">httpContextBase</param>
         /// <returns></returns>
         public static ControllerContext CreateControllerContext(Controller controller, HttpContextBase contextBase)
         {
              controllerContext = new ControllerContext
                (
               contextBase,
               new RouteData(),
                controller);
             return controllerContext;
         }


         /// <summary>
         /// 创建ControllerContext
         /// </summary>
         /// <param name="controller">controller</param>
         /// <param name="url">访问的url地址</param>
         /// <param name="httpMethod">访问的方法（get,post）</param>
         /// <param name="name">路由名称</param>
         /// <param name="pattern">路由格式</param>
         /// <param name="obj">路由默认值</param>
         /// <returns></returns>
         public static ControllerContext CreateControllerContext(Controller controller, string url, string httpMethod, string name, string pattern, string obj)
         {
              controllerContext = new ControllerContext
                 (
                 CreateHttpContext(),
                 GetRouteData(url, httpMethod, name, pattern, obj),
                 controller);
             return controllerContext;
         }

         /// <summary>
         /// 创建ControllerContext
         /// </summary>
         /// <param name="controller">controller</param>
         /// <param name="contextBase">HttpContextBase</param>
         /// <param name="url">访问的url地址</param>
         /// <param name="httpMethod">访问的方法（get,post）</param>
         /// <param name="name">路由名称</param>
         /// <param name="pattern">路由格式</param>
         /// <param name="obj">路由默认值</param>
         /// <returns></returns>
         public static ControllerContext CreateControllerContext(Controller controller, HttpContextBase contextBase, string url, string httpMethod, string name, string pattern, string obj)
         {
              controllerContext = new ControllerContext
                 (
                 contextBase,
                 GetRouteData(url, httpMethod, name, pattern, obj),
                 controller);
             return controllerContext;
         }

         /// <summary>
         /// 创建HttpContextBase
         /// </summary>
         /// <returns></returns>
         public static HttpContextBase CreateHttpContext()
         {
             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>();
             response
                 .Setup(rsp => rsp.ApplyAppPathModifier(Moq.It.IsAny<string>()))
                 .Returns((string s) => s);

             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);

             return context.Object;
         }

         #region Private Method
         private static HttpContextBase CreateHttpContext(string url, string httpMethod)
         {
             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>();
             response
                 .Setup(rsp => rsp.ApplyAppPathModifier(Moq.It.IsAny<string>()))
                 .Returns((string s) => s);

             request.Setup(req => req.AppRelativeCurrentExecutionFilePath).Returns(url);
             request.Setup(req => req.HttpMethod).Returns(httpMethod);

             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);

             return context.Object;
         }

         private static RouteData GetRouteData(string url, string httpMethod, string name, string pattern, string obj)
         {
             RouteTable.Routes.MapRoute(name, pattern, obj);
             var routeData =
                 RouteTable.Routes.
                 GetRouteData(CreateHttpContext(url, httpMethod));
             return routeData;
         }
         #endregion

     }
 }

三、在mvc中使用MockHttpContextFactory

通过之前编写MvcContextMockFactory类我们在MVC单元测试中可以轻松的实现对HttpContext的模拟

首先创建一个控制器

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web.Mvc;
namespace Stephen.Sample.ASPNETMvc.MockUnitTest.Controller
{
   public class HomeController:System.Web.Mvc.Controller
    {
      public ViewResult Index()
      {
          ViewData["controller"] = RouteData.Values["controller"];
          ViewData["action"] = RouteData.Values["action"];
          return View("Index");
      }
    }
}

因为控制器中需要获取RouteData，RouteData来自于Controller下的ControllerContext

单元测试中调用MockHttpContextFactory模拟ControllerContext，完成单元测试。

using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MvcContextMock;
using Stephen.Sample.ASPNETMvc.MockUnitTest.Controller;

namespace Stephen.Sample.ASPNETMvc.MockUnitTest.TestProject
{
    [TestClass]
    public class HomeControllerUnitTest
    {
        [TestMethod]
        public void IndexActionTest()
        {
            var homeController = new HomeController();
            homeController.ControllerContext = MvcContextMock.MvcContextMockFactory.CreateControllerContext(homeController, "~/Home/Index", "get", "DefaultRoute", "{controller}/{action}", null);
            ViewResult result= homeController.Index();
            Assert.AreEqual("Index",result.ViewName);
            Assert.AreEqual("Home",result.ViewData["controller"]);
            Assert.AreEqual("Index", result.ViewData["action"]);
        }
    }
}

对于更简单的HttpContext在MockHttpContextFactory中有专用的方法生成与ControllerContext原理类似。