Don’t call us we’ll call you

public class ListWithChangedEvent : ArrayList
{
    // An event that clients can use to be notified whenever the
    // elements of the list change.
    public event ChangedEventHandler ChangedEvent;

    // Override some of the methods that can change the list;
    // invoke event after each
    public override int Add(object value)
    {
        int i = base.Add(value);
        if (ChangedEvent != null)
        {
            ChangedEvent(this, EventArgs.Empty);
        }
        return i;
    }
}

[Test]
public void TestEventWorks()
{
    // Create a new list.
    ListWithChangedEvent list = new ListWithChangedEvent();

    // Try with one listener
    // add a listener
    list.Changed += new ChangedEventHandler(list_Changed);
    using (RecordExpectations record = RecorderManager.StartRecording())
    {
        // expect to be called when adding to list
        list_Changed(list, EventArgs.Empty);
    }  
    // Add item to the list.
    list.Add("item 1");
    // make sure it was called
    MockManager.Verify();
}

// dummy method that is used as a placeholder
void list_Changed(object sender, EventArgs e)
{
    throw new Exception("The method or operation is not implemented.");
}
  

public void Example()
{
   Button button = new Button();
   button.Click += new EventHandler(button_Click);
}

private void button_Click(object sender, EventArgs e)
{
   // Do Somethings here
}   

[Test]
public void TestThatExampleWorksWhenButtonClicked()
{
    using (RecordExpectations record = RecorderManager.StartRecording())
    {
        // mock next button and the event registration
        Button mockedButton = new Button();
        mockedButton.Click += null;
    }
    // invoke our test method that registers to button.Click
    Example();
    // Fire the event
    RecorderManager.LastMockedEvent.Fire(this, EventArgs.Empty);
    // here we test that Example works correctly
    //...

    MockManager.Verify();
  }