}

  private transient @Nullable ImmutableSet<Entry<K, V>> cachedEntrySet = null;

  @Override
  public final ImmutableSet<Entry<K, V>> entrySet() {
    if (cachedEntrySet != null) {
      return cachedEntrySet;
    }
    return cachedEntrySet = createEntrySet();
  }

  abstract ImmutableSet<Entry<K, V>> createEntrySet();

  private transient @Nullable ImmutableSet<K> cachedKeySet = null;

  @Override

  }

  public void testCreate_empty() {
    assertEquals(ImmutableSet.of(), ContiguousSet.create(Range.closedOpen(1, 1), integers()));
    assertEquals(ImmutableSet.of(), ContiguousSet.closedOpen(1, 1));
    assertEquals(ImmutableSet.of(), ContiguousSet.create(Range.openClosed(5, 5), integers()));
    assertEquals(
        ImmutableSet.of(), ContiguousSet.create(Range.lessThan(Integer.MIN_VALUE), integers()));
    assertEquals(

          return key.toString();
        }
      };

  private CacheBuilderFactory factoryWithAllKeyStrengths() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();

        .addEqualityGroup(ImmutableSet.of(), ImmutableSet.of())
        .addEqualityGroup(ImmutableSet.of(1), ImmutableSet.of(1), ImmutableSet.of(1, 1))
        .addEqualityGroup(ImmutableSet.of(1, 2, 1), ImmutableSet.of(2, 1, 1))
        .testEquals();
  }

  @GwtIncompatible("internals")
  public void testControlsArraySize() {
    ImmutableSet.Builder<String> builder = new ImmutableSet.Builder<String>();

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(ImmutableSet.of(), ImmutableSet.of())
        .addEqualityGroup(ImmutableSet.of(1), ImmutableSet.of(1), ImmutableSet.of(1, 1))
        .addEqualityGroup(ImmutableSet.of(1, 2, 1), ImmutableSet.of(2, 1, 1))
        .testEquals();
  }

  /**

    if (mapEntries.isEmpty()) {
      return of();
    }
    ImmutableMap.Builder<K, ImmutableSet<V>> builder =
        new ImmutableMap.Builder<>(mapEntries.size());
    int size = 0;

    for (Entry<K, ImmutableCollection.Builder<V>> entry : mapEntries) {
      K key = entry.getKey();
      ImmutableSet.Builder<? extends V> values = (ImmutableSet.Builder<V>) entry.getValue();

          ImmutableList.Builder::combine,
          ImmutableList.Builder::build);

  private static final Collector<Object, ?, ImmutableSet<Object>> TO_IMMUTABLE_SET =
      Collector.of(
          ImmutableSet::builder,
          ImmutableSet.Builder::add,
          ImmutableSet.Builder::combine,
          ImmutableSet.Builder::build);

  @GwtIncompatible
  private static final Collector<Range<Comparable<?>>, ?, ImmutableRangeSet<Comparable<?>>>

          ImmutableList.Builder::combine,
          ImmutableList.Builder::build);

  private static final Collector<Object, ?, ImmutableSet<Object>> TO_IMMUTABLE_SET =
      Collector.of(
          ImmutableSet::builder,
          ImmutableSet.Builder::add,
          ImmutableSet.Builder::combine,
          ImmutableSet.Builder::build);

  @GwtIncompatible
  private static final Collector<Range<Comparable<?>>, ?, ImmutableRangeSet<Comparable<?>>>

        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))
        .withMaximumSizes(ImmutableSet.of(400, 1000))
        .withInitialCapacities(ImmutableSet.of(0, 1, 10, 100, 1000))
        .withExpireAfterWrites(
            ImmutableSet.of(

        .withKeyStrengths(ImmutableSet.of(Strength.STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.copyOf(Strength.values()))
        .withConcurrencyLevels(ImmutableSet.of(1, 4, 16, 64))
        .withMaximumSizes(ImmutableSet.of(0, 1, 10, 100, 1000))
        .withInitialCapacities(ImmutableSet.of(0, 1, 10, 100, 1000))
        .withExpireAfterWrites(
            ImmutableSet.of(