@Test(expected = IllegalArgumentException.class)
public void shouldErrorIfFeaturesLabelsHasEmptyKey() {

  Map<String, String> badLabels = Map.of("", "empty");
  List<FeatureSpecV2> badFeatureSpecs =
      getTestSpec().getFeaturesList().stream()
          .map(featureSpec -> featureSpec.toBuilder().putAllLabels(badLabels).build())
          .collect(Collectors.toList());
  FeatureTableSpec badSpec = getTestSpec().toBuilder().addAllFeatures(badFeatureSpecs).build();
  FeatureTableValidator.validateSpec(badSpec);
}