Selenium 脚本稳定性问题

运行一个星期前升至更久前的脚本，，，出现如下错误提示

elementNotVisibleException was unhandled by user code。

经过询问大侠，说我的脚本不够健全，也就是稳定性的问题，需要增加一些判断等待，那需要封装一些等待方法

  public static void WaitUnit<T>(this IWebDriver webDriver, Func<IWebDriver, T> func, int seconds = 20)
        {
            var wait = new WebDriverWait(webDriver, TimeSpan.FromSeconds(seconds));
            wait.Until(func);
        }

        /// <summary>
        /// 强制让webdriver等待，直到给定的元素(by)存在于DOM之中
        /// </summary>
        public static void WaitElementExist(this IWebDriver webDriver, By by, int seconds = 20)
        {
            var wait = new WebDriverWait(webDriver, TimeSpan.FromSeconds(seconds));
            wait.Until(ExpectedConditions.ElementExists(by));
        }

        /// <summary>
        /// 强制让webdriver等待，直到给定的元素(by)的CSS属性visiblity的值为visible
        /// </summary>
        public static void WaitElementVisible(this IWebDriver webDriver, By by, int seconds = 20)
        {
            var wait = new WebDriverWait(webDriver, TimeSpan.FromSeconds(seconds));
            wait.Until(ExpectedConditions.ElementIsVisible(by));
        }

        /// <summary>
        /// 强制让webdriver等待，直到当前的浏览器title包含指定的字符串
        /// </summary>
        public static void WaitTitleContains(this IWebDriver webDriver, string title, int seconds = 20)
        {
            var wait = new WebDriverWait(webDriver, TimeSpan.FromSeconds(seconds));
            wait.Until(ExpectedConditions.TitleContains(title));
        }

        /// <summary>
        /// 强制让webdriver等待，直到当前的浏览器title与给定读的title一致
        /// </summary>
        public static void WaitTitleIs(this IWebDriver webDriver, string title, int seconds = 20)
        {
            var wait = new WebDriverWait(webDriver, TimeSpan.FromSeconds(seconds));
            wait.Until(ExpectedConditions.TitleIs(title));
        }

        /// <summary>
        /// Executes JavaScript in the context of the currently selected frame or window.
        /// </summary>
        /// <param name="webDriver">IWebDriver实例</param>
        /// <param name="jsCode">js代码(最好的web里面先执行一次，确保正确性)</param>
        public static void ExecJavascript(this IWebDriver webDriver, string jsCode)
        {
            ((IJavaScriptExecutor)webDriver).ExecuteScript(jsCode);
        }