以下設置不匹配，WPF MVVM單元測試與起訂量

Question

我在WPF編寫單元測試與起訂量來測試用戶是否點擊了一個YesNoCancel MessageBox中的「是」按鈕時，他們關閉窗戶。在我CloseCommand我在我的視圖模型給出了當用戶關閉窗口下面的消息：

var result = _messageSvc.Show(
    "Do you want to save changes?", 
    "Save Changes", 
    Services.MessageBoxButton.YesNoCancel, 
    Services.MessageBoxIcon.Question, 
    Services.MessageBoxResult.Yes); 

我_messageSvc是一個自定義郵件服務以顯示消息框內部的私有實例。下面是服務的代碼：

public interface IMessageSvc 
{ 
    void Show(string message); 
    MessageBoxResult Show(string message, string caption, MessageBoxButton buttons, MessageBoxIcon icon, MessageBoxResult defaultResult = 0); 
} 

public class MessageSvc : IMessageSvc 
{ 
    public void Show(string message) 
    { 
     MessageBox.Show(message); 
    } 

    public MessageBoxResult Show(string message, string caption, MessageBoxButton buttons, MessageBoxIcon icon, MessageBoxResult defaultResult) 
    { 
     return (MessageBoxResult)MessageBox.Show(message, caption, (System.Windows.MessageBoxButton)buttons, (System.Windows.MessageBoxImage)icon, (System.Windows.MessageBoxResult)defaultResult); 
    } 
} 

注：MessageBoxButton，MessageBoxIcon，並MessageBoxResult是枚舉我在同一個文件進行模仿什麼.NET提供開箱即用的。我不向他們展示這裏的可讀性

我的單元測試的緣故：

[TestMethod] 
public void ShouldAskToSaveOnCloseRespondYesTest() 
{ 
    // Mock and setup initial user data 
    var u= new User 
    { 
     UserId = 1, 
     UserName = "FirstName LastName", 
     FavoriteColor = "Blue" 
    }; 
    mainViewModel.UserInfo= new UserInfoDtoWrapper(u); 

    // assert the data has not changed yet 
    Assert.IsFalse(mainViewModel.UserInfo.IsChanged); 

    // change the user data 
    mainViewModel.UserInfo.UserName= "LastName FirstName"; 

    // assert the data has changed 
    Assert.IsTrue(mainViewModel.UserInfo.IsChanged); 

    // execute window closing 
    mainViewModel.CloseCommand.Execute(new object()); 

    // verify messagebox shows and the 'Yes' button is clicked 
    // this will then save the changes made to the user instance 
    var messageBox = new Mock<IMessageSvc>(); 
    messageBox.Setup(x => x.Show(It.Is<string>(y => y == "Do you want to save changes?"), 
     It.Is<string>(y => y == "Save Changes"), 
     It.Is<MessageBoxButton>(y => y == MessageBoxButton.YesNoCancel), 
     It.Is<MessageBoxIcon>(y => y == MessageBoxIcon.Question), 
     It.Is<MessageBoxResult>(y => y == MessageBoxResult.Yes))) 
     .Returns(MessageBoxResult.Yes); 

    messageBox.Verify(); 
} 

的錯誤出現在messageBox.Verify()線，但是從我所看到的，我做正確。我需要獲取消息框的返回值，以繼續測試用戶單擊「是」按鈕後發生的情況，所以我不想在內部使用帶有Linq查詢的Verify，而是需要捕獲結果。

謝謝

Answer 1

這是行不通的。你在你的測試代碼2個問題：

1. 你先火CloseCommand（假定調用IMessageSvc.Show方法），然後才安裝了該服務的模擬。

2. 您爲服務設置了一個新的模擬，但不使用它。

要糾正這些錯誤：

• 更改順序，這是一個正確的「安排」 - 「行動」 - 「斷言」爲了
• 注入你的嘲笑服務視圖模型使用依賴注入

下面是一個例子：

class MainViewModel 
{ 
    private readonly IMessageSvc _messageSvc; 

    public MainViewModel(IMessageSvc svc) 
    { 
     this._messageSvc = svc; 
    } 
} 

[TestMethod] 
public void ShouldAskToSaveOnCloseRespondYesTest() 
{ 
    // Arrange 
    var messageBox = new Mock<IMessageSvc>(); 
    messageBox.Setup(x => x.Show(It.Is<string>(y => y == "Do you want to save changes?"), 
     It.Is<string>(y => y == "Save Changes"), 
     It.Is<MessageBoxButton>(y => y == MessageBoxButton.YesNoCancel), 
     It.Is<MessageBoxIcon>(y => y == MessageBoxIcon.Question), 
     It.Is<MessageBoxResult>(y => y == MessageBoxResult.Yes))) 
     .Returns(MessageBoxResult.Yes) 
     .Verifiable(); 

    var mainViewModel = new MainViewModel(messageBox.Object); 

    // Act 
    mainViewModel.CloseCommand.Execute(new object()); 

    // Assert 
    messageBox.Verify(); 
} 

Answer 2

當前你正在設置你的模擬方法後測試將調用它的代碼。重新安排您的測試AAA (Arrange, Act, Assert)模式像這樣：

var messageBox = new Mock<IMessageSvc>(); 
messageBox.Setup(x => x.Show(It.Is<string>(y => y == "Do you want to save changes?"), 
    It.Is<string>(y => y == "Save Changes"), 
    It.Is<MessageBoxButton>(y => y == MessageBoxButton.YesNoCancel), 
    It.Is<MessageBoxIcon>(y => y == MessageBoxIcon.Question), 
    It.Is<MessageBoxResult>(y => y == MessageBoxResult.Yes))) 
    .Returns(MessageBoxResult.Yes); 

mainViewModel.CloseCommand.Execute(new object()); 

messageBox.Verify(x => x.Show(It.Is<string>(y => y == "Do you want to save changes?"), 
    It.Is<string>(y => y == "Save Changes"), 
    It.Is<MessageBoxButton>(y => y == MessageBoxButton.YesNoCancel), 
    It.Is<MessageBoxIcon>(y => y == MessageBoxIcon.Question), 
    It.Is<MessageBoxResult>(y => y == MessageBoxResult.Yes)));