public static MetadataUpdate fromJson(String json) {
    return JsonUtil.parse(json, MetadataUpdateParser::fromJson);
  }
@Test
  public void testSetLocationFromJson() {
    String action = MetadataUpdateParser.SET_LOCATION;
    String location = "s3://bucket/warehouse/tbl_location";
    String json = String.format("{\"action\":\"%s\",\"location\":\"%s\"}", action, location);
    MetadataUpdate expected = new MetadataUpdate.SetLocation(location);
    assertEquals(action, expected, MetadataUpdateParser.fromJson(json));
  }