def test_merge_by_id_no_key(self):
        schema = {
            "mergeStrategy": "arrayMergeById",
        }

        a = [
            {"id": "A", "field": 1},
        ]

        b = [
            {'field': 2}
        ]

        merger = jsonmerge.Merger(schema)

        base = None
        base = merger.merge(base, a)
        base = merger.merge(base, b)

        # it should ignore array elements that do not have the id
        self.assertEqual(base, a)