@Test
public void defaultMapper() throws Exception {

  try (PatchSetSerializer serializer = new PatchSetSerializer()) {
    PatchSet patchSet = new PatchSet("road1", new ArrayList<>());
    byte[] bytes = serializer.serialize("topic", patchSet);
    ObjectReader reader = new ObjectMapper().readerFor(PatchSet.class);
    assertThat(reader.readValue(bytes), is(patchSet));
  }
}