MVC：使用 HttpContextWrapper 转换后如何模拟

Question

Public Class PhotoUploadController

   Public ReadOnly Property IsMobileDevice As Boolean
       Get
          Return ControllerContext.HttpContext.GetOverriddenBrowser.IsMobileDevice
       End Get
   End Property

   Function SavePhoto(model As PhotoUploadModel) As ActionResult
       If Not String.IsNullOrWhiteSpace(Request.Files(0).FileName) And IsMobileDevice Then
    Return View("Index", model)
   End If       
   End Function

End Class   

<TestMethod()>
 Public Sub SavePhoto_Test()

   Dim permissions As New List(Of String)
   permissions.Add(Constants.VIEW_ACCOUNTS)
   Dim mUser As New MockUser(ListOfPermissions:=permissions)
   Dim controller As PhotoUploadController = New PhotoUploadController(mUser, New PhotoRepository)
   System.Web.HttpContext.Current = New HttpContext(New HttpRequest("test", "http://www.yahoo.com/accounts", ""), New HttpResponse(New System.IO.StringWriter()))

   Dim browserMock = MockRepository.GenerateStub(Of HttpBrowserCapabilities)()
   browserMock.Expect(Function(b) b.IsMobileDevice).Return(True)
   System.Web.HttpContext.Current.Request.Browser = browserMock

   Dim currentContext As HttpContextBase = MockRepository.GenerateStub(Of HttpContextWrapper)(System.Web.HttpContext.Current)
   currentContext.Expect(Function(fn) fn.Request.Files(0).FileName).Return("test.txt")
   'If I comment out the two lines above and uncomment the below line the IsMobile is set in the SavePhoto actionresult otherwise it is null.
   'Dim currentContext As HttpContextBase = New HttpContextWrapper(System.Web.HttpContext.Current)
   controller.ControllerContext = New ControllerContext(currentContext, New System.Web.Routing.RouteData(), controller)

   Dim model As New PhotoUploadModel(mUser)

   Dim result As ActionResult = controller.SavePhoto(model)

   Assert.IsNotNull(result)
   Assert.IsInstanceOfType(result, GetType(ViewResult))

End Sub

Answer 1

以下答案应该会引导您走向正确的方向。 请注意，我不是 VB.NET 开发人员。如果我的语法不正确，请耐心等待。我实际上使用了一个工具将 C# 转换为 VB :)

首先你的单元测试有几个问题

一个。您的测试方法名称写得不好，它不能反映您的确切意图。

b.存根/设置期望并不容易

ControllerContext.HttpContext.GetOverriddenBrowser.IsMobileDevice

GetOverriddenBrowser 是一种静态扩展方法。所以它是不可模拟的。

c。您的断言正在验证两件事。一是结果是否为null，二是结果的类型是ViewResult。我会亲自测试后者，结果的类型。如果结果不是，测试会以任何方式抛出异常。通过限制为一个断言，您可以更轻松地编写测试方法名称。

为了避免删除 .IsMobileDevice 的痛苦，我将简单地在控制器中引入一个属性/或多或少一个 Func/delegate 属性。我会在构造函数中设置 IsMobileDevice，如下所示。这样我就可以在我的单元测试中简单地存根从 IsMobileDeviceFunc 返回的值。

Imports System.Web.WebPages

Public Interface IUser
End Interface

Public Interface IPhotoRepository
End Interface

Public Class PhotoUploadModel
End Class

Public Class PhotoUploadController
    Inherits Controller

    Private m_IsMobileDeviceFunc As Func(Of Boolean)

    Public Sub New(user As IUser, repository As IPhotoRepository)
        IsMobileDeviceFunc = Function() 
        ControllerContext.HttpContext.GetOverriddenBrowser().IsMobileDevice
    End Sub

    Public Property IsMobileDeviceFunc() As Func(Of Boolean)
        Get
            Return m_IsMobileDeviceFunc
        End Get
        Set(value As Func(Of Boolean))
           m_IsMobileDeviceFunc = Value
        End Set
    End Property


    Public Function SavePhoto(model As PhotoUploadModel) As ActionResult
       Dim isMobD = IsMobileDeviceFunc

       If Not String.IsNullOrWhiteSpace(Request.Files(0).FileName) And isMobD() Then
           Return View("Index", model)
       End If

       Return New EmptyResult()
    End Function

End Class

单元测试

 <TestMethod()> Public Sub SavePhoto_ActionExecute_ActionResultIsTypeOfViewResult()

    Dim sut = New PhotoUploadController(MockRepository.GenerateStub(Of IUser)(), MockRepository.GenerateStub(Of IPhotoRepository)())
    sut.IsMobileDeviceFunc = Function() True
    Dim currentContext = MockRepository.GenerateStub(Of HttpContextBase)()
    Dim requestStub = MockRepository.GenerateStub(Of HttpRequestBase)()
    requestStub.Expect(Function(x) x.Files(0).FileName).[Return]("foo")
    currentContext.Expect(Function(x) x.Request).[Return](requestStub)
    sut.ControllerContext = New ControllerContext(currentContext, New RouteData(), sut)

    Dim result As ActionResult = sut.SavePhoto(New PhotoUploadModel())

    Assert.IsInstanceOfType(result, GetType(ViewResult))
 End Sub

希望这会为您指明正确的方向。