* depend on the element values, such as a {@link SortedSet}, or on the insertion ordering, such
   * as a {@link LinkedHashSet}. All list tests and sorted-collection tests automatically specify
   * this feature.
   */
  KNOWN_ORDER,

  /**
   * Indicates that a collection has a different {@link Object#toString} representation than most

/**
 * Implementation of {@link ImmutableSet} backed by a non-empty {@link java.util.EnumSet}.
 *
 * @author Jared Levy
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
final class ImmutableEnumSet<E extends Enum<E>> extends ImmutableSet<E> {
  static <E extends Enum<E>> ImmutableSet<E> asImmutable(EnumSet<E> set) {

  }

  /**
   * Creates an empty {@code TreeMultimap} instance using explicit comparators. Neither comparator
   * may be null; use {@link Ordering#natural()} to specify natural order.
   *
   * @param keyComparator the comparator that determines the key ordering
   * @param valueComparator the comparator that determines the value ordering
   */

 * regular sets respectively. For the sorted sets, it's a thin wrapper around {@link
 * java.util.TreeSet}.
 *
 * @see ImmutableSortedSet
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements Set<E> {
  ImmutableSet() {}

  public static <E> Collector<E, ?, ImmutableSet<E>> toImmutableSet() {

    try {
      ImmutableBiMap.copyOf(map);
      fail();
    } catch (IllegalArgumentException expected) {
      assertThat(expected.getMessage()).containsMatch("1|2");
      // We don't specify which of the two dups should be reported.
    }
  }

  // TODO(b/172823566): Use mainline testToImmutableBiMap once CollectorTester is usable to java7.
  public void testToImmutableBiMap_java7_combine() {

    }
  }

  public void testLinkedHashMap() {
    LinkedHashMap<Integer, Integer> map = Maps.newLinkedHashMap();
    assertEquals(Collections.emptyMap(), map);
  }

  @SuppressWarnings("serial")
  public void testLinkedHashMapWithInitialMap() {
    Map<String, String> map =
        new LinkedHashMap<String, String>(
            ImmutableMap.of(
                "Hello", "World",

    }
  }

  public void testLinkedHashMap() {
    LinkedHashMap<Integer, Integer> map = Maps.newLinkedHashMap();
    assertEquals(Collections.emptyMap(), map);
  }

  @SuppressWarnings("serial")
  public void testLinkedHashMapWithInitialMap() {
    Map<String, String> map =
        new LinkedHashMap<String, String>(
            ImmutableMap.of(
                "Hello", "World",

 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use ImmutableMap.of or another implementation")
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
@ElementTypesAreNonnullByDefault
public abstract class ImmutableMap<K, V> implements Map<K, V>, Serializable {

  /**

   * @since 7.0
   */
  public static List<Character> charactersOf(CharSequence sequence) {
    return new CharSequenceAsList(checkNotNull(sequence));
  }

  @SuppressWarnings("serial") // serialized using ImmutableList serialization
  private static final class StringAsImmutableList extends ImmutableList<Character> {

    private final String string;

    StringAsImmutableList(String string) {

  public static <E> QueueTestSuiteBuilder<E> using(TestQueueGenerator<E> generator) {
    return new QueueTestSuiteBuilder<E>().usingGenerator(generator);
  }

  private boolean runCollectionTests = true;

  /**
   * Specify whether to skip the general collection tests. Call this method when testing a
   * collection that's both a queue and a list, to avoid running the common collection tests twice.
   * By default, collection tests do run.
   */