@Test
void update() {

  ElasticsearchSettings settings = new ElasticsearchSettings(clusterSettings);
  ByteSizeValue oldValue = settings.getSettingValue(Settings.Key.PPL_QUERY_MEMORY_LIMIT);
  ElasticsearchSettings.Updater updater =
      settings.new Updater(Settings.Key.PPL_QUERY_MEMORY_LIMIT);
  updater.accept(new ByteSizeValue(0L));
  ByteSizeValue newValue = settings.getSettingValue(Settings.Key.PPL_QUERY_MEMORY_LIMIT);
  assertNotEquals(newValue.getBytes(), oldValue.getBytes());
}