public void testKeySetCharacteristics() {
    int expectedCharacteristics = Spliterator.ORDERED | Spliterator.NONNULL;
    assertThat(
            immutableEnumMap(ImmutableMap.of(AnEnum.A, "a"))
                    .keySet()
                    .spliterator()
                    .characteristics()
                & expectedCharacteristics)
        .isEqualTo(expectedCharacteristics);
  }

    }

    /**
     * Returns a Set view of the keys contained in this map.
     *
     * @return a set view of the keys contained in this map
     */
    @Override
    public Set<String> keySet() {
        return parent.keySet();
    }

    /**
     * Returns a Collection view of the values contained in this map.
     *
     * @return a collection view of the values contained in this map
     */
    @Override

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE})
  public void testReplaceNonEmptyValues() {
    List<K> keys = copyToList(multimap().keySet());
    List<V> values = asList(v0(), v2(), v3());

    for (K k : keys) {
      resetContainer();

      int size = multimap().size();
      Collection<V> oldKeyValues = copyToList(multimap().get(k));

  // views

  /**
   * Returns an immutable set of the distinct keys in this multimap, in the same order as they
   * appear in this multimap.
   */
  @Override
  public ImmutableSet<K> keySet() {
    return map.keySet();
  }

  @Override
  Set<K> createKeySet() {
    throw new AssertionError("unreachable");
  }

  /**

      return delegate;
    }

    @Override
    public Set<K> keySet() {
      return new ForwardingSet<K>() {
        @Override
        protected Set<K> delegate() {
          return delegate.keySet();
        }

        @Override
        public Iterator<K> iterator() {
          return Iterators.unmodifiableIterator(delegate.keySet().iterator());
        }

        @Override

    assertTrue(multimap().put(k1(), v4()));
    assertTrue(asMapEntrySet.remove(asMapEntry0));
    assertEquals(1, multimap().size());
    assertContentsInOrder(multimap().keySet(), k1());
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testAsMapEntrySetIteratorRemovePropagatesToMultimap() {

      return standardEquals(object);
    }

    @Override
    public int hashCode() {
      return standardHashCode();
    }

    @Override
    public Set<K> keySet() {
      return new StandardKeySet();
    }

    @Override
    public Collection<V> values() {
      return new StandardValues();
    }

    @Override
    public String toString() {

        parent.putAll(m);
    }

    @Override
    public void clear() {
        parent.clear();
    }

    @Override
    public Set<K> keySet() {
        // return original keys
        return parent.keySet();
    }

    @Override
    public Collection<V> values() {
        return parent.values();
    }

    @Override
    public Set<Entry<K, V>> entrySet() {

    }

    @Override
    public Enumeration<Object> keys() {
        return getProperties().keys();
    }

    @Override
    public Set<Object> keySet() {
        return getProperties().keySet();
    }

    @Override
    public void list(final PrintStream out) {
        getProperties().list(out);
    }

    @Override
    public void list(final PrintWriter out) {

    TestContainerGenerator<Map<K, V>, Entry<K, V>> generator = mapGenerator.getInnerGenerator();
    if (generator instanceof TestSortedMapGenerator
        && ((TestSortedMapGenerator<K, V>) generator).create().keySet() instanceof SortedSet) {
      return new MapSortedKeySetGenerator<>(mapGenerator);
    } else {
      return new MapKeySetGenerator<>(mapGenerator);
    }
  }