POST_ORDER {
      @Override
      <T> Iterable<T> view(T root, TreeTraverser<T> viewer) {
        return viewer.postOrderTraversal(root);
      }
    },
    BREADTH_FIRST {
      @Override
      <T> Iterable<T> view(T root, TreeTraverser<T> viewer) {
        return viewer.breadthFirstTraversal(root);
      }
    };

    abstract <T> Iterable<T> view(T root, TreeTraverser<T> viewer);
  }

    Iterable<Integer> iterable = iterable(Collections.<Integer>emptySet());
    assertThat(ImmutableIntArray.copyOf(iterable)).isSameInstanceAs(ImmutableIntArray.of());
  }

  public void testCopyOf_iterable_notCollection_nonempty() {
    List<Integer> list = Arrays.asList(0, 1, 3);
    ImmutableIntArray iia = ImmutableIntArray.copyOf(iterable(list));
    list.set(2, 2);

    Iterable<Double> iterable = iterable(Collections.<Double>emptySet());
    assertThat(ImmutableDoubleArray.copyOf(iterable)).isSameInstanceAs(ImmutableDoubleArray.of());
  }

  public void testCopyOf_iterable_notCollection_nonempty() {
    List<Double> list = Arrays.asList(0.0, 1.0, 3.0);
    ImmutableDoubleArray iia = ImmutableDoubleArray.copyOf(iterable(list));
    list.set(2, 2.0);

   *
   * <p>Some algorithms that operate on a {@code PredecessorsFunction} may produce undesired results
   * if the returned {@link Iterable} contains duplicate elements. Implementations of such
   * algorithms should document their behavior in the presence of duplicates.
   *
   * <p>The elements of the returned {@code Iterable} must each be:
   *
   * <ul>
   *   <li>Non-null

   *
   * <p>Some algorithms that operate on a {@code SuccessorsFunction} may produce undesired results
   * if the returned {@link Iterable} contains duplicate elements. Implementations of such
   * algorithms should document their behavior in the presence of duplicates.
   *
   * <p>The elements of the returned {@code Iterable} must each be:
   *
   * <ul>
   *   <li>Non-null

    throw ArrayIndexOutOfBoundsException("length=$arrayLength, offset=$offset, count=$offset")
  }
}

internal fun <T> interleave(
  a: Iterable<T>,
  b: Iterable<T>,
): List<T> {
  val ia = a.iterator()
  val ib = b.iterator()

  return buildList {
    while (ia.hasNext() || ib.hasNext()) {
      if (ia.hasNext()) {
        add(ia.next())
      }

  public void testOf_empty() {
    Iterable<String> iterable = MinimalIterable.<String>of();
    Iterator<String> iterator = iterable.iterator();
    assertFalse(iterator.hasNext());
    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(IllegalStateException.class, () -> iterable.iterator());
  }

  public void testOf_one() {
    Iterable<String> iterable = MinimalIterable.of("a");

    public Iterable<UseIterable<? extends Iterable<?>>>
        wildcardOfImplicitBoundedIsSubtypeOfWildcardOfExplicitlyBounded(
            List<UseIterable<?>> withImplicitBounds) {
      return isSubtype(withImplicitBounds);
    }

    @TestSubtype(suppressGetSupertype = true, suppressGetSubtype = true)
    public Iterable<UseSerializableIterable<? extends Iterable<?>>>

    }

    @Override
    public Iterable<V> order(List<V> insertionOrder) {
      K k =
          ((TestMultimapGenerator<K, V, M>) multimapGenerator.getInnerGenerator())
              .sampleKeys()
              .e0();
      List<Entry<K, V>> entries = new ArrayList<>();
      for (V v : insertionOrder) {
        entries.add(mapEntry(k, v));
      }
      Iterable<Entry<K, V>> ordered = multimapGenerator.order(entries);

    /**
     * Returns an {@link Iterable} that wraps an {@link IndexedIterator} for use in a for-each statement.
     *
     * @param <T> the element type
     * @param iterable the iterable (must not be {@literal null})
     * @return an {@link Iterable} wrapping an {@link IndexedIterator}
     */
    public static <T> Iterable<Indexed<T>> indexed(final Iterable<T> iterable) {
        assertArgumentNotNull("iterable", iterable);