public void GetRequiredElementTest()
        {
            var actual = XmlExtensions.GetRequiredElement(m_xml, "/a/b");

            Assert.AreEqual <string>("Bear", actual, "The value of /a/b is wrong");

            try
            {
                XmlExtensions.GetRequiredElement(m_xml, "/a/dddd");
                Assert.Fail("Expected exception of type '" + typeof(ArgumentException).Name + "' but none was thrown.");
            }
            catch (ArgumentException) { }
            catch (Exception __e)
            {
                Assert.Fail("Expected exception of type ArgumentException, but " + __e.GetType().ToString() + " was generated instead.");
            }
        }