assertNotSame(features, FeatureUtil.impliedFeatures(features));
  }

  public void testImpliedFeatures_returnsImpliedFeatures() throws Exception {
    Set<Feature<?>> features;

    features = Sets.<Feature<?>>newHashSet(ExampleDerivedFeature.DERIVED_FEATURE_1);
    assertTrue(FeatureUtil.impliedFeatures(features).isEmpty());

    features = Sets.<Feature<?>>newHashSet(ExampleDerivedFeature.DERIVED_FEATURE_2);

    assertNotSame(features, FeatureUtil.impliedFeatures(features));
  }

  public void testImpliedFeatures_returnsImpliedFeatures() throws Exception {
    Set<Feature<?>> features;

    features = Sets.<Feature<?>>newHashSet(ExampleDerivedFeature.DERIVED_FEATURE_1);
    assertTrue(FeatureUtil.impliedFeatures(features).isEmpty());

    features = Sets.<Feature<?>>newHashSet(ExampleDerivedFeature.DERIVED_FEATURE_2);

   * @return the implied set of features
   */
  public static Set<Feature<?>> impliedFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> impliedSet = new LinkedHashSet<>();
    Queue<Feature<?>> queue = new ArrayDeque<>(features);
    while (!queue.isEmpty()) {
      Feature<?> feature = queue.remove();
      for (Feature<?> implied : feature.getImpliedFeatures()) {
        if (!features.contains(implied) && impliedSet.add(implied)) {

import com.google.common.collect.testing.DerivedCollectionGenerators.MapValueCollectionGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.Feature;
import com.google.common.collect.testing.features.MapFeature;
import com.google.common.collect.testing.testers.MapClearTester;

          .put(MapFeature.SUPPORTS_PUT, CollectionFeature.SUPPORTS_ADD)
          .build();

  Set<Feature<?>> computeMultimapGetFeatures(Set<Feature<?>> multimapFeatures) {
    Set<Feature<?>> derivedFeatures = Helpers.copyToSet(multimapFeatures);
    for (Entry<Feature<?>, Feature<?>> entry : GET_FEATURE_MAP.entries()) {
      if (derivedFeatures.contains(entry.getKey())) {
        derivedFeatures.add(entry.getValue());

   * @return the implied set of features
   */
  public static Set<Feature<?>> impliedFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> impliedSet = new LinkedHashSet<>();
    Queue<Feature<?>> queue = new ArrayDeque<>(features);
    while (!queue.isEmpty()) {
      Feature<?> feature = queue.remove();
      for (Feature<?> implied : feature.getImpliedFeatures()) {
        if (!features.contains(implied) && impliedSet.add(implied)) {

  @CanIgnoreReturnValue
  public B withFeatures(Iterable<? extends Feature<?>> features) {
    for (Feature<?> feature : features) {
      this.features.add(feature);
    }
    return self();
  }

  public Set<Feature<?>> getFeatures() {
    return Collections.unmodifiableSet(features);
  }

  // Name

  private @Nullable String name;

import com.google.common.collect.testing.DerivedCollectionGenerators.MapValueCollectionGenerator;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.Feature;
import com.google.common.collect.testing.features.MapFeature;
import com.google.common.collect.testing.testers.MapClearTester;

    testers.add(MultisetIteratorTester.class);
    testers.add(MultisetSerializationTester.class);
    return testers;
  }

  private static Set<Feature<?>> computeEntrySetFeatures(Set<Feature<?>> features) {
    Set<Feature<?>> derivedFeatures = new HashSet<>(features);
    derivedFeatures.remove(CollectionFeature.GENERAL_PURPOSE);
    derivedFeatures.remove(CollectionFeature.SUPPORTS_ADD);

          .put(MapFeature.SUPPORTS_PUT, CollectionFeature.SUPPORTS_ADD)
          .build();

  Set<Feature<?>> computeMultimapGetFeatures(Set<Feature<?>> multimapFeatures) {
    Set<Feature<?>> derivedFeatures = Helpers.copyToSet(multimapFeatures);
    for (Entry<Feature<?>, Feature<?>> entry : GET_FEATURE_MAP.entries()) {
      if (derivedFeatures.contains(entry.getKey())) {
        derivedFeatures.add(entry.getValue());