@Test
  @Override
  public void testToString() {
    super.testToString();

    MutableMultimap<String, Integer> multimap = this.newMultimapWithKeysValues("One", 1, "One", 2);
    String toString = multimap.toString();
    Assert.assertTrue("{One=[1, 2]}".equals(toString) || "{One=[2, 1]}".equals(toString));
  }
 @Benchmark
 public void parallel_eager_forkjoin_ec() {
   MutableMultimap<Alphagram, String> groupBy = FJIterate.groupBy(this.ecWords, Alphagram::new);
   CompositeFastList<RichIterable<String>> select =
       FJIterate.select(
           groupBy.multiValuesView(),
           iterable -> iterable.size() >= SIZE_THRESHOLD,
           new CompositeFastList<>(),
           false);
   Collection<String> collect =
       FJIterate.collect(
           select
               .toSortedList(Comparators.<RichIterable<String>>byIntFunction(RichIterable::size))
               .asReversed(),
           iterable -> iterable.size() + ": " + iterable);
   FJIterate.forEach(collect, Procedures.cast(e -> Assert.assertFalse(e.isEmpty())));
 }