public static String toJson(MetadataUpdate metadataUpdate) {
    return toJson(metadataUpdate, false);
  }
@Test
  public void testSetCurrentSchemaToJson() {
    String action = MetadataUpdateParser.SET_CURRENT_SCHEMA;
    int schemaId = 6;
    String expected = String.format("{\"action\":\"%s\",\"schema-id\":%d}", action, schemaId);
    MetadataUpdate update = new MetadataUpdate.SetCurrentSchema(schemaId);
    String actual = MetadataUpdateParser.toJson(update);
    assertThat(actual)
        .as("Set current schema should convert to the correct JSON value")
        .isEqualTo(expected);
  }