def METHOD_NAME(self):
    records = [
        Record(0, 0),
        Record(2, 0),
        Record(1, 2)
    ]
    # Record 1 have parent_id(2) greater than record_id(1)
    with self.assertRaises(ValueError) as err:
        BuildTree(records)
    self.assertEqual(type(err.exception), ValueError)
    self.assertEqual(err.exception.args[0], "Node parent_id should be smaller than it's record_id.")