}

  /** Returns an immutable sorted set containing a single element. */
  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1) {
    return new RegularImmutableSortedSet<>(ImmutableList.of(e1), Ordering.natural());
  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.

  @CollectionSize.Require(SEVERAL)
  public void testRetainAll_countIgnored() {
    resetContainer(getSubjectGenerator().create(e0(), e2(), e1(), e0()));
    assertTrue(getList().retainAll(asList(e0(), e1())));
    assertContentsInOrder(getList(), e0(), e1(), e0());
  }

   * Collections#singleton} for code consistency, {@code null} rejection, and because the return
   * type conveys the immutability guarantee.
   */
  public static <E> ImmutableSet<E> of(E e1) {
    return new SingletonImmutableSet<>(e1);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to

    return ImmutableSortedSet.of(e1, e2);
  }

  @Override
  protected <E extends Comparable<? super E>> SortedSet<E> of(E e1, E e2, E e3) {
    return ImmutableSortedSet.of(e1, e2, e3);
  }

  @Override
  protected <E extends Comparable<? super E>> SortedSet<E> of(E e1, E e2, E e3, E e4) {
    return ImmutableSortedSet.of(e1, e2, e3, e4);
  }

  @Override

     */
    List<E> disjointList = asList(e3(), e4());
    disjoint = new Target(disjointList, "disjoint");
    superset = new Target(MinimalCollection.of(e0(), e1(), e2(), e3(), e4()), "superset");
    nonEmptyProperSubset = new Target(MinimalCollection.of(e1()), "subset");
    sameElements = new Target(asList(createSamplesArray()), "sameElements");
    containsDuplicates =

  protected final K k0() {
    return e0().getKey();
  }

  protected final V v0() {
    return e0().getValue();
  }

  protected final K k1() {
    return e1().getKey();
  }

  protected final V v1() {
    return e1().getValue();
  }

  protected final K k2() {
    return e2().getKey();
  }

  protected final V v2() {
    return e2().getValue();
  }

  }

  @Override
  protected Map<Object, Integer> makePopulatedMap() {
    Colliders colliders = new Colliders();
    return ImmutableMap.of(
        colliders.e0(), 0,
        colliders.e1(), 1,
        colliders.e2(), 2,
        colliders.e3(), 3);
  }

  @Override
  protected Object getKeyNotInPopulatedMap() {
    return new Colliders().e4();
  }

  @Override

                    CopyUtil.copy(in, tempFile);
                } catch (final Exception e1) {
                    if (tempFile != null && tempFile.exists() && !tempFile.delete()) {
                        logger.warn("Failed to delete {}", tempFile.getAbsolutePath());
                    }
                    throw e1;
                }

    return ImmutableMap.of();
  }

  @Override
  protected Map<Integer, UnhashableObject> makePopulatedMap() {
    Unhashables unhashables = new Unhashables();
    return ImmutableMap.of(0, unhashables.e0(), 1, unhashables.e1(), 2, unhashables.e2());
  }

  @Override
  protected Integer getKeyNotInPopulatedMap() {
    return 3;
  }

  @Override
  protected UnhashableObject getValueNotInPopulatedMap() {

  protected abstract <E extends Comparable<? super E>> Set<E> of(E e1, E e2, E e3);

  protected abstract <E extends Comparable<? super E>> Set<E> of(E e1, E e2, E e3, E e4);

  protected abstract <E extends Comparable<? super E>> Set<E> of(E e1, E e2, E e3, E e4, E e5);

  protected abstract <E extends Comparable<? super E>> Set<E> of(
      E e1, E e2, E e3, E e4, E e5, E e6, E... rest);