* 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();

            .withFeatures(
                CollectionSize.ONE,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        ListTestSuiteBuilder.using(new ImmutableSetAsListGenerator())
            .named("ImmutableSet.asList")
            .withFeatures(
                CollectionSize.ANY,

            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        SetTestSuiteBuilder.using(new DegeneratedImmutableSetGenerator())
            .named(ImmutableSetTest.class.getName() + ", degenerate")
            .withFeatures(

                unfiltered.add("zzz");
                return Collections2.filter(unfiltered, NOT_YYY_ZZZ);
              }
            })
        .named("Collections2.filter")
        .withFeatures(
            CollectionFeature.SUPPORTS_ADD,
            CollectionFeature.SUPPORTS_REMOVE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)

   * 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();

            .named("ImmutableList")
            .withFeatures(CollectionSize.ANY, SERIALIZABLE, ALLOWS_NULL_QUERIES)
            .createTestSuite());
    suite.addTest(
        ListTestSuiteBuilder.using(new BuilderAddAllListGenerator())
            .named("ImmutableList, built with Builder.add")
            .withFeatures(CollectionSize.ANY, SERIALIZABLE, ALLOWS_NULL_QUERIES)
            .createTestSuite());

                            .result();
                      }
                    }.sortedCopy(insertionOrder);
                  }
                })
            .named("TreeMultimap nullsFirst")
            .withFeatures(
                MapFeature.ALLOWS_NULL_KEYS,
                MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES,
                MapFeature.GENERAL_PURPOSE,

            .named("ImmutableList")
            .withFeatures(CollectionSize.ANY, SERIALIZABLE, ALLOWS_NULL_QUERIES)
            .createTestSuite());
    suite.addTest(
        ListTestSuiteBuilder.using(new BuilderAddAllListGenerator())
            .named("ImmutableList, built with Builder.add")
            .withFeatures(CollectionSize.ANY, SERIALIZABLE, ALLOWS_NULL_QUERIES)
            .createTestSuite());

                unfiltered.add("zzz");
                return Collections2.filter(unfiltered, NOT_YYY_ZZZ);
              }
            })
        .named("Collections2.filter")
        .withFeatures(
            CollectionFeature.SUPPORTS_ADD,
            CollectionFeature.SUPPORTS_REMOVE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)

                            .result();
                      }
                    }.sortedCopy(insertionOrder);
                  }
                })
            .named("TreeMultimap nullsFirst")
            .withFeatures(
                MapFeature.ALLOWS_NULL_KEYS,
                MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES,
                MapFeature.GENERAL_PURPOSE,