Moq - mock.Raise 应该在测试单元中引发事件，而无需安装

Question

我有一个演示者类，它附加了注入视图的事件。 现在我想测试演示者对事件的正确反应。

这是视图接口 IView：

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

这是实现 IView 的视图：

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);
        }
    }
}

这是被测试的演示者：

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();
    }
}

这是测试装置测试 MyPresenter：

[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>());
    }
}

我正在使用最小起订量 4。可以做我想做的吗？

Answer 1

不需要通过论证吗？您的事件签名是 EventHandler，即
（对象发送者，EventArgs e）。

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

我从未使用过您在此处指定的重载...不过，它似乎不正确。

Answer 2

您已将 UpdateView() 声明为接受字符串，但您的演示者调用没有字符串参数（或默认值）：

Inspiration:

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

Declaration:

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

Verification:

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

FWIW，我认为您视图中的事件有点麻烦，一个简单的更改就是：

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);
    }
}

然后您可以只验证与视图的交互，而无需处理其他事件：

    presenter.SelectItem("Burrito!");

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