public void TestUnwrapElement()
{
var n1 = new HElement("span", "Content");
var root = new HElement("div", new HElement("strong", new HElement("em", n1)));
Assert.Equal("<div><strong><em><span>Content</span></em></strong></div>", root.ToString());
Assert.Same(n1, n1.Unwrap());
Assert.Equal("<div><strong><span>Content</span></strong></div>", root.ToString());
n1 = null;
Assert.Null(n1.Unwrap());
}