def test_add_nodes(self):
        rootTag = 'Root'
        root = Node(rootTag)
        firstLevelTag = 'FirstLevel'
        firstLevel = Node(firstLevelTag)
        root += firstLevel
        firstLevel2 = Node(firstLevelTag)
        root += firstLevel2
        firstLevel2ndTag = 'FirstLevel2ndTag'
        firstLevel3 = Node(firstLevel2ndTag)
        root = root + firstLevel3
        self.assertIn(firstLevel, root.children)
        self.assertIn(firstLevel2, root.children)
        self.assertIn(firstLevel3, root.children)