CollectorTester.of(
            ImmutableMultiset.<Multiset.Entry<String>, String>toImmutableMultiset(
                Multiset.Entry::getElement, Multiset.Entry::getCount),
            equivalence)
        .expectCollects(ImmutableMultiset.of())
        .expectCollects(
            ImmutableMultiset.of("a", "a", "b", "c", "c", "c"),

        Multiset.Entry<K> transform(Map.Entry<K, Collection<V>> backingEntry) {
          return new Multisets.AbstractEntry<K>() {
            @Override
            @ParametricNullness
            public K getElement() {
              return backingEntry.getKey();
            }

            @Override
            public int getCount() {
              return backingEntry.getValue().size();
            }

        Multiset.Entry<K> transform(Map.Entry<K, Collection<V>> backingEntry) {
          return new Multisets.AbstractEntry<K>() {
            @Override
            @ParametricNullness
            public K getElement() {
              return backingEntry.getKey();
            }

            @Override
            public int getCount() {
              return backingEntry.getValue().size();
            }