CollectionFeature(Feature<? super Collection>... implied) {
    this.implied = Helpers.copyToSet(implied);
  }

  @Override
  public Set<Feature<? super Collection>> getImpliedFeatures() {
    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    CollectionFeature[] value() default {};

    testers.add(BiMapClearTester.class);
    return testers;
  }

  enum NoRecurse implements Feature<Void> {
    INVERSE;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  @Override
  protected List<TestSuite> createDerivedSuites(
      FeatureSpecificTestSuiteBuilder<

   * created for them.
   */
  enum NoRecurse implements Feature<@Nullable Void> {
    SUBMAP,
    DESCENDING;

    @Override
    public Set<Feature<? super @Nullable Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *

    testers.add(BiMapClearTester.class);
    return testers;
  }

  enum NoRecurse implements Feature<Void> {
    INVERSE;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  @Override
  protected List<TestSuite> createDerivedSuites(
      FeatureSpecificTestSuiteBuilder<

    return new MultisetTestSuiteBuilder<E>().usingGenerator(generator);
  }

  public enum NoRecurse implements Feature<Void> {
    NO_ENTRY_SET;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  @SuppressWarnings("rawtypes") // class literals
  @Override
  protected List<Class<? extends AbstractTester>> getTesters() {

   * created for them.
   */
  enum NoRecurse implements Feature<Void> {
    SUBMULTISET,
    DESCENDING;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  /** Two bounds (from and to) define how to build a subMultiset. */
  enum Bound {
    INCLUSIVE,
    EXCLUSIVE,
    NO_BOUND;
  }

    return new MultisetTestSuiteBuilder<E>().usingGenerator(generator);
  }

  public enum NoRecurse implements Feature<Void> {
    NO_ENTRY_SET;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  @SuppressWarnings("rawtypes") // class literals
  @Override
  protected List<Class<? extends AbstractTester>> getTesters() {

   * created for them.
   */
  enum NoRecurse implements Feature<Void> {
    SUBMULTISET,
    DESCENDING;

    @Override
    public Set<Feature<? super Void>> getImpliedFeatures() {
      return Collections.emptySet();
    }
  }

  /** Two bounds (from and to) define how to build a subMultiset. */
  enum Bound {
    INCLUSIVE,
    EXCLUSIVE,
    NO_BOUND;
  }

    Set<Feature<?>> derivedFeatures =
        Helpers.copyToSet(computeMultimapGetFeatures(multimapFeatures));
    if (derivedFeatures.remove(CollectionSize.ANY)) {
      derivedFeatures.addAll(CollectionSize.ANY.getImpliedFeatures());
    }
    derivedFeatures.remove(CollectionSize.ZERO);
    return derivedFeatures;
  }

  private static class AsMapGenerator<K, V, M extends Multimap<K, V>>

    Set<Feature<?>> derivedFeatures =
        Helpers.copyToSet(computeMultimapGetFeatures(multimapFeatures));
    if (derivedFeatures.remove(CollectionSize.ANY)) {
      derivedFeatures.addAll(CollectionSize.ANY.getImpliedFeatures());
    }
    derivedFeatures.remove(CollectionSize.ZERO);
    return derivedFeatures;
  }

  private static class AsMapGenerator<K, V, M extends Multimap<K, V>>