def test_basic_relation(self): parent = TreeNode(9) node = TreeNode(8) left = TreeNode(6) right = TreeNode(7) node.parent = parent node.left = left node.right = right self.assertEqual(id(node.parent), id(parent)) self.assertEqual(id(node.left), id(left)) self.assertEqual(id(node.right), id(right)) self.assertEqual(id(left.parent), id(node)) self.assertEqual(id(right.parent), id(node)) self.assertEqual(id(node.parent), id(parent)) self.assertEqual(id(parent.left), id(node)) self.assertTrue(parent.key > left.key) self.assertTrue(parent > left)