如何在尝试单元测试时触发初始化方法?

我有下面的覆盖,可以使用formsidentity对象对cookie执行一些操作。但是当我在单元测试中实例化一个控制器时,这个方法不会被触发。你知道怎么做吗?

   protected override void Initialize(System.Web.Routing.RequestContext requestContext)
    {
        base.Initialize(requestContext);

        // Grab the user's login information from FormsAuth
        _userState = new UserState();
        if (this.User.Identity != null && this.User.Identity is FormsIdentity)
            this._userState.FromString(((FormsIdentity)this.User.Identity).Ticket.UserData);

        // have to explicitly add this so Master can see untyped value
        this.UserState = _userState;
        //this.ViewData["ErrorDisplay"] = this.ErrorDisplay;

        // custom views should also add these as properties
    }