How to setup expectation on the event subscription removal?

public class Controller
{
    public AddressCreationViewControlsState State { get; set; }

    public void Unsubsribe()
    {
        this.State.PropertyChanged -= new PropertyChangedEventHandler(State_PropertyChanged);
    }

    void State_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        throw new NotImplementedException();
    }
}

public class AddressCreationViewControlsState : ViewControlsStateBase
{
}

public abstract class ViewControlsStateBase : INotifyPropertyChanged
{
    #region INotifyPropertyChanged Members
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (null != handler)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }
    #endregion
}

[TestMethod]
[Isolated]
public void CanUnsubsribe()
{
    Controller controller = new Controller();
    AddressCreationViewControlsState state = Isolate.Fake.Instance<AddressCreationViewControlsState>();

    controller.State = state;

    controller.Unsubsribe();

    Isolate.Verify.WasCalledWithAnyArguments(() => state.PropertyChanged -= null);
}