mock Request on Controller in ASP.Net MVC ?

這是一個論壇提問形式的，看到就收藏了一下。

原地址:http://stackoverflow.com/questions/970198/how-to-mock-the-request-on-controller-in-asp-net-mvc
How to mock the Request on Controller in ASP.Net MVC ?
我有一個用ASP.Net MVC framework 架構下的Controller.
public class HomeController:Controller{
  public ActionResult Index()
    {
      if (Request.IsAjaxRequest())
        {
          //do some ajaxy stuff
        }
      return View("Index");
    }
}
我想用通過RhinoMocks 來測試這個Controller

var mocks = new MockRepository();
var mockedhttpContext = mocks.DynamicMock<HttpContextBase>();
var mockedHttpRequest = mocks.DynamicMock<HttpRequestBase>();
SetupResult.For(mockedhttpContext.Request).Return(mockedHttpRequest);

var controller = new HomeController();
controller.ControllerContext = new ControllerContext(mockedhttpContext, new RouteData(), controller);
var result = controller.Index() as ViewResult;
Assert.AreEqual("About", result.ViewName);
但是我卻得到如下的錯誤:

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Exception System.ArgumentNullException: System.ArgumentNullException : Value cannot be null. Parameter name: request at System.Web.Mvc.AjaxRequestExtensions.IsAjaxRequest(HttpRequestBase request)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
雖然Request object 在這個Controller 中沒有初始化.但是我嘗試著通過以下的方法來解決這個問題。
我用 Moq(mock) 來代替 RhinoMocks，來做相同的測試。
var request = new Mock<HttpRequestBase>();
// Not working - IsAjaxRequest() is static extension method and cannot be mocked
// request.Setup(x => x.IsAjaxRequest()).Returns(true /* or false */);
// use this
request.SetupGet(x => x.Headers["X-Requested-With"]).Returns("XMLHttpRequest");

var context = new Mock<HttpContextBase>();
context.SetupGet(x => x.Request).Returns(request.Object);
var controller = new HomeController(Repository, LoginInfoProvider);
controller.ControllerContext = new ControllerContext(context.Object, new RouteData(), controller);
var result = controller.Index() as ViewResult;
Assert.AreEqual("About", result.ViewName);
但是又會得到如下的錯誤資訊:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Exception System.ArgumentException: System.ArgumentException : Invalid setup on a non-overridable member: x => x.Headers["X-Requested-With"] at Moq.Mock.ThrowIfCantOverride(Expression setup, MethodInfo methodInfo)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
這一次，看來我是真的不能重設 Request 當中的header.我怎麼樣才能設定裡面的值，用RhinoMocks 或 Moq都可以。(呵呵這個也是我關心的)

## 6 level
Using Moq:
var request = new Mock<HttpRequestBase>();
// Not working - IsAjaxRequest() is static extension method and cannot be mocked
// request.Setup(x => x.IsAjaxRequest()).Returns(true /* or false */);
// use this
request.SetupGet(x => x.Headers).Returns(
    new System.Net.WebHeaderCollection {
        {"X-Requested-With", "XMLHttpRequest"}
    });

var context = new Mock<HttpContextBase>();
context.SetupGet(x => x.Request).Returns(request.Object);

var controller = new YourController();
controller.ControllerContext = new ControllerContext(context.Object, new RouteData(), controller);
更新一下:
用Mock Request.Headers["X-Requested-With"] or Request["X-Requested-With"] 替換掉 Request.IsAjaxRequest()

回複:==========
我執行後又出現這個資訊:"The Type argument for method 'ISetupGetter<T, TProperty>Moq.Mock<T>.SetupGet<Tpropert>.... cannot be infered from uage. Try specifying the type arguments explicitly.:('ISetupGetter<T, TProperty>Moq.Mock<T>.SetupGet<Tpropert>.... 中的參數類型不明確,請顯示聲明參數的類型)要想把這個錯誤解決的話我應該怎麼寫"var request="這一句呢？

更新一下我的問題-是Request.IsAjaxRequest()並非Request.IsAjaxRequest 把你的問題也更新一下吧.

仍然產生:Exception System.ArgumentException: System.ArgumentException : Invalid setup on a non-overridable member: x => x.IsAjaxRequest() at Moq.Mock.ThrowIfCantOverride(Expression setup, MethodInfo methodInfo)

問題是 那個IsAjaxRequest() 是個靜態擴充方法是不能被mocked的我已經更了我的回答。

是不是這樣寫呢context.SetupGet(x => x.Request).Returns(request.Object); 你上面那個方法在Returen的時候少一個字母's';所以會有 Exception System.ArgumentException: System.ArgumentException : Invalid 中的X沒有被重構 這裡x => x.Headers["X-Requested-With"]；結果就會拋出 (Expression setup, MethodInfo methodInfo) 這個錯誤資訊.

# 1 level
你只需要偽造一個HttpContextBase 把它引入到你的Controller中就可以了像這樣:
controller.ControllerContext =
new ControllerContext(mockedHttpContext, new RouteData(), controller);
現在你看到了如何偽造這些Form conllection，剛好和你的標題有點相似:Mocking the HttpRequest in ASP.NET MVC

mockedHttpContext 需要什麼才能仿造呢？好像就是這個HttpContextBase() 吧。而HttpContextBase() 又是不能接受零個參數的.

用mocking framework為什麼不能變向的來間接構建呢？

我這樣試了一下:var mocks = new MockRepository(); var mockedhttpContext = mocks.DynamicMock<HttpContextBase>(); var mockedHttpRequest = mocks.DynamicMock<HttpRequestBase>(); SetupResult.For(mockedhttpContext.Request).Return(mockedHttpRequest); var controller = new HomeController(Repository, LoginInfoProvider); controller.ControllerContext = new mockedhttpContext, new RouteData(), controller); var result = controller.Index() as ViewResult;
不過好像還是有相同的錯誤.

# 0 level
AjaxRequest 不是一個擴充方法嗎，所以用Rhino 的mock 可以這樣寫:
protected HttpContextBase BuildHttpContextStub(bool isAjaxRequest)
    {
        var httpRequestBase = MockRepository.GenerateStub<HttpRequestBase>();   
        if (isAjaxRequest)
        {
            httpRequestBase.Stub(r => r["X-Requested-With"]).Return("XMLHttpRequest");
        }

        var httpContextBase = MockRepository.GenerateStub<HttpContextBase>();
        httpContextBase.Stub(c => c.Request).Return(httpRequestBase);

        return httpContextBase;
    }

    // Build controller
    ....
    controller.ControllerContext = new ControllerContext(BuildHttpContextStub(true), new RouteData(), controller);