public void testAddInOrderElement(){
Tree tree = new Tree();
Element e1 = new Element();
e1.setUid("A");
e1.setXpath("/html/body/table[@id='mt']");
e1.addAttribute(TAG, "table");
tree.addElement(e1);
Element e2 = new Element();
e2.setUid("B");
e2.setXpath("/html/body/table[@id='mt']/tbody/tr/th[3]");