* called more than once to add features in multiple groups.
   */
  @CanIgnoreReturnValue
  public B withFeatures(Feature<?>... features) {
    return withFeatures(asList(features));
  }

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

                return Collections.checkedMap(map, String.class, String.class);
              }
            })
        .named("checkedMap/HashMap")
        .withFeatures(
            MapFeature.GENERAL_PURPOSE,
            MapFeature.ALLOWS_NULL_KEYS,
            MapFeature.ALLOWS_NULL_VALUES,
            MapFeature.ALLOWS_ANY_NULL_QUERIES,

              @Override
              public Set<String> create(String[] elements) {
                return emptySet();
              }
            })
        .named("emptySet")
        .withFeatures(CollectionFeature.SERIALIZABLE, CollectionSize.ZERO)
        .suppressing(suppressForEmptySet())
        .createTestSuite();
  }

  public Test testsForSingletonSet() {
    return SetTestSuiteBuilder.using(

                return Collections.checkedMap(map, String.class, String.class);
              }
            })
        .named("checkedMap/HashMap")
        .withFeatures(
            MapFeature.GENERAL_PURPOSE,
            MapFeature.ALLOWS_NULL_KEYS,
            MapFeature.ALLOWS_NULL_VALUES,
            MapFeature.ALLOWS_ANY_NULL_QUERIES,

                    }
                    return multimap;
                  }
                })
            .named("synchronized ArrayListMultimap")
            .withFeatures(
                MapFeature.ALLOWS_NULL_KEYS,
                MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES,
                MapFeature.GENERAL_PURPOSE,

              @Override
              public List<String> create(String[] elements) {
                return emptyList();
              }
            })
        .named("emptyList")
        .withFeatures(CollectionFeature.SERIALIZABLE, CollectionSize.ZERO)
        .suppressing(suppressForEmptyList())
        .createTestSuite();
  }

  public Test testsForSingletonList() {
    return ListTestSuiteBuilder.using(

              @Override
              public List<String> create(String[] elements) {
                return emptyList();
              }
            })
        .named("emptyList")
        .withFeatures(CollectionFeature.SERIALIZABLE, CollectionSize.ZERO)
        .suppressing(suppressForEmptyList())
        .createTestSuite();
  }

  public Test testsForSingletonList() {
    return ListTestSuiteBuilder.using(

            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .named("Multisets.unmodifiableMultiset[TreeMultiset]")
            .createTestSuite());

    suite.addTest(
        MultisetTestSuiteBuilder.using(unionGenerator())

              public Queue<String> create(String[] elements) {
                return new ArrayDeque<>(MinimalCollection.of(elements));
              }
            })
        .named("ArrayDeque")
        .withFeatures(
            CollectionFeature.GENERAL_PURPOSE, CollectionFeature.KNOWN_ORDER, CollectionSize.ANY)
        .suppressing(suppressForArrayDeque())
        .createTestSuite();
  }

      derivedSuites.add(
          SetTestSuiteBuilder.using(
                  new ReserializedSetGenerator<E>(parentBuilder.getSubjectGenerator()))
              .named(getName() + " reserialized")
              .withFeatures(computeReserializedCollectionFeatures(parentBuilder.getFeatures()))
              .suppressing(parentBuilder.getSuppressedTests())
              .withSetUp(parentBuilder.getSetUp())