def test_merge_by_id_bad_base_type(self):
        schema = {
            'mergeStrategy': 'arrayMergeById'
        }

        head = []
        base = {'foo': 'bar'}

        merger = jsonmerge.Merger(schema)
        with self.assertRaises(BaseInstanceError) as cm:
            merger.merge(base, head)

        self.assertEqual(cm.exception.value.ref, '#')