def registry = new DefaultSerializerRegistry()
        registry.register(Long, longSerializer)
        registry.register(Integer, intSerializer)
        def serializer = registry.build(Number)

        expect:
        serialize(123L, serializer) == 123L
        serialize(123, serializer) == 123
        toBytes(123L, serializer).length == toBytes(123L, longSerializer).length + 1
    }