def test_get_is_descendant(self):
a = CWNode('a')
root = CWRootNode([a])
tree = CWTree(root)
self.assertTrue(tree.get_is_descendant(a, root))
self.assertFalse(tree.get_is_descendant(a, a))
self.assertFalse(tree.get_is_descendant(root, a))
