Moq - mock.Raise 應該在沒有設置的情況下在測試單元中引發事件

Question

我有一個演示者類，它附加了注入視圖的事件。 現在我想測試演示者對事件的正確反應。

這是視圖接口IView ：

public interface IView 
{
    event EventHandler MyEvent;
    void UpdateView(string test);
}

這是實現IView的視圖：

public partial class MyView : IView
{
    public event EventHandler MyEvent;

    public MyView()
    {
        this.combo.SelectedIndexChanged += this.OnSelectedIndexChanged;
    }

    public void UpdateView(string test)
    {
        this.textBox.Text = test;
    }

    private OnSelectedIndexChanged(Object sender, EventArgs e)
    {
        if (this.MyEvent != null)
        {
            this.MyEvent(sender, e);
        }
    }
}

這是被測試的演示者：

public class MyPresenter
{
    private IView _view;
    public MyPresenter(IView view)
    {
        this._view = view;
        this._view.MyEvent += this.OnMyEvent;
    }

    private void OnMyEvent(Object sender, EventArgs e)
    {
        this._view.UpdateView();
    }
}

這是測試MyPresenter的測試裝置：

[TestClass]
public class MyPresenterFixture()
{
    private MyPresenter testee;
    private Mock<IView> mockView;

    [TestMethod]
    public void ShouldReactOnMyEvent()
    {
        // arrange
        this.mockView = new Mock<IView>(MockBehavior.Strict);
        this.testee = new MyPresenter(this.mockView.Object);

        // act
        this.mockView.Raise(mock => mock.MyEvent += null); // this does not fire

        // assert and verify
        this.mockView.Verify(mock => mock.UpdateView(It.IsAny<string>());
    }
}

我正在使用 Moq 4。是否可以做我想做的事？

Answer 1

你不需要傳遞參數嗎？ 您的事件簽名是EventHandler ，即
(object sender, EventArgs e) 。

this.mockView.Raise(mock => mock.MyEvent += null, new EventArgs());

我從未使用過您在此處指定的重載……不過，它似乎不正確。

Answer 2

您已將 UpdateView() 聲明為接受字符串，但您的演示者調用沒有字符串參數（或默認值）：

調用：

private void OnMyEvent(Object sender, EventArgs e)
{
    this._view.UpdateView();
}

宣言：

public void UpdateView(string test)
{
    this.textBox.Text = test;
}

確認：

mockView.Verify(mock => mock.UpdateView(It.IsAny<string>());

FWIW，我認為您認為的事件有點麻煩，一個簡單的更改是：

public interface IView
{
    void UpdateText(string test);
}

public class MyPresenter
{
    private readonly IView _view;
    public MyPresenter(IView view)
    {
        _view = view;
    }

    private void SelectItem(string item)
    {
        _view.UpdateText(item);
    }
}

public partial class MyView : IView
{
    private readonly MyPresenter _presenter;

    public MyView()
    {
        _presenter = new MyPresenter(this);
        combo.SelectedIndexChanged += OnSelectedIndexChanged;
    }

    public void UpdateText(string test)
    {
        textBox.Text = test;
    }

    private OnSelectedIndexChanged(Object sender, EventArgs e)
    {
        _presenter.SelectItem(combo.SelectedItem);
    }
}

然后你可以只驗證與視圖的交互，而無需處理額外的事件：

    presenter.SelectItem("Burrito!");

    mockView.Verify(mock => mock.UpdateView("Burrito!");