@Test
public void serialize() throws Exception {

    Update<TestModel> update = Update.of(TestModel.builder()
            .email("test@example.com")
            .birthday(LocalDate.of(2017, 3, 1))
            .name("Test")
            .build(),
            ImmutableSet.of("email", "birthday"),
            ImmutableSet.of("country"));
    ObjectMapper mapper = new ObjectMapper()
            .registerModule(new JavaTimeModule());
    String json = mapper.writeValueAsString(update);
    assertEquals("{\"email\":\"test@example.com\",\"birthday\":\"2017-03-01\",\"country\":null}", json);
}