Set<String> set2 = Sets.newHashSet(elements);
                    set2.add(samples().e4());
                    return Sets.intersection(set1, set2);
                  }
                })
            .named("Sets.intersection")
            .withFeatures(CollectionSize.ANY, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

    suite.addTest(