def test_oneof_multiple_validate(self):

        schema = {
            'oneOf': [
                {
                    'type': 'array',
                    'maxItems': 3,
                    'mergeStrategy': 'append'
                },
                {
                    'type': 'array',
                    'minItems': 2,
                    'mergeStrategy': 'overwrite'
                }
            ]
        }

        merger = jsonmerge.Merger(schema)

        base = [1]
        base = merger.merge(base, [2])

        self.assertEqual(base, [1, 2])

        base = [1, 2]

        with self.assertRaises(HeadInstanceError) as cm:
            base = merger.merge(base, [3, 4])