using System;

using System.Xml;

using HtmlAgilityPack;

public class Program

{

    public static void Main()

    {

        var html = @"<div class='test'>

        <ul>

            <li><b>Test1</b>Test1 Text</li>

            <li><b>Test2</b>Test2 Text</li>

        </ul>

";

        HtmlDocument doc = new HtmlDocument();

        doc.LoadHtml(html);

        HtmlNode node = doc.DocumentNode.SelectSingleNode("(//div[@class='test']//text()[normalize-space()])[last()]");

        Console.WriteLine(node.InnerText);

    }

}