implements Serializable {
  final Equivalence<E> elementEquivalence;

  PairwiseEquivalence(Equivalence<E> elementEquivalence) {
    this.elementEquivalence = Preconditions.checkNotNull(elementEquivalence);
  }

  @Override
  protected boolean doEquivalent(Iterable<T> iterableA, Iterable<T> iterableB) {
    Iterator<T> iteratorA = iterableA.iterator();

  }

  private static class CountingIterable implements Iterable<String> {
    int count = 0;

    @Override
    public Iterator<String> iterator() {
      count++;
      return Iterators.forArray("a", "b", "a");
    }
  }

  public void testCopyOf_plainIterable() {
    CountingIterable iterable = new CountingIterable();
    Set<String> set = copyOf(iterable);
    assertEquals(2, set.size());

  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");

    return 0;
  }

  @Override
  public <E extends @Nullable Object> List<E> sortedCopy(Iterable<E> iterable) {
    return Lists.newArrayList(iterable);
  }

  @Override
  public <E> ImmutableList<E> immutableSortedCopy(Iterable<E> iterable) {
    return ImmutableList.copyOf(iterable);
  }

  @SuppressWarnings("unchecked")
  @Override
  public <S extends @Nullable Object> Ordering<S> reverse() {

   * always true when the iterable has fewer than two elements.
   */
  public static <T extends @Nullable Object> boolean isInOrder(
      Iterable<? extends T> iterable, Comparator<T> comparator) {
    checkNotNull(comparator);
    Iterator<? extends T> it = iterable.iterator();
    if (it.hasNext()) {
      T prev = it.next();
      while (it.hasNext()) {
        T next = it.next();
        if (comparator.compare(prev, next) > 0) {

  }

  private static boolean isEmpty(Iterable<?> iterable) {
    return iterable instanceof Collection
        ? ((Collection<?>) iterable).isEmpty()
        : !iterable.iterator().hasNext();
  }

  public static void assertEmpty(Iterable<?> iterable) {
    if (!isEmpty(iterable)) {
      fail("Not true that " + iterable + " is empty");
    }
  }

   * they are returned by the iterable's iterator.
   *
   * @since 12.0
   */
  public static <E> ArrayDeque<E> newArrayDeque(Iterable<? extends E> elements) {
    if (elements instanceof Collection) {
      return new ArrayDeque<>((Collection<? extends E>) elements);
    }
    ArrayDeque<E> deque = new ArrayDeque<>();
    Iterables.addAll(deque, elements);
    return deque;

    Iterable<String> iterable = asList("a", "b");
    Iterator<String> cycle = Iterators.cycle(iterable);
    cycle.next();
    assertThrows(UnsupportedOperationException.class, () -> cycle.remove());
  }

  public void testCycleRemoveAfterHasNext() {
    Iterable<String> iterable = Lists.newArrayList("a");
    Iterator<String> cycle = Iterators.cycle(iterable);
    assertTrue(cycle.hasNext());

      Function<T, ? extends Iterable<T>> nodeToChildrenFunction) {
    checkNotNull(nodeToChildrenFunction);
    return new TreeTraverser<T>() {
      @Override
      public Iterable<T> children(T root) {
        return nodeToChildrenFunction.apply(root);
      }
    };
  }

  /** Returns the children of the specified node. Must not contain null. */
  public abstract Iterable<T> children(T root);

  /**

    PUT_BOOLEAN() {
      @Override
      void performAction(Random random, Iterable<? extends PrimitiveSink> sinks) {
        boolean value = random.nextBoolean();
        for (PrimitiveSink sink : sinks) {
          sink.putBoolean(value);
        }
      }
    },
    PUT_BYTE() {
      @Override
      void performAction(Random random, Iterable<? extends PrimitiveSink> sinks) {
        int value = random.nextInt();