public static MetadataUpdate fromJson(String json) {
    return JsonUtil.parse(json, MetadataUpdateParser::fromJson);
  }
@Test
  public void testSetDefaultSortOrderFromJson() {
    String action = MetadataUpdateParser.SET_DEFAULT_SORT_ORDER;
    int sortOrderId = 2;
    String json = String.format("{\"action\":\"%s\",\"sort-order-id\":%d}", action, sortOrderId);
    MetadataUpdate expected = new MetadataUpdate.SetDefaultSortOrder(sortOrderId);
    assertEquals(action, expected, MetadataUpdateParser.fromJson(json));
  }