public void FileFor_Value_Int()
        {
            var model = new Model1()
            {
                PropInt = 1
            };
            var helper = new HtmlTagHelper <Model1>(model);

            var propExpression = Expr((Model1 m) => m.PropInt);
            var tag            = helper.FileFor(propExpression);

            AssertValid(tag, "input", "PropInt", type: "file", value: null);
        }