Iterable<String> iterable = asList("a", "b");
    Iterator<String> cycle = Iterators.cycle(iterable);
    cycle.next();
    try {
      cycle.remove();
      fail("no exception thrown");
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testCycleRemoveAfterHasNext() {
    Iterable<String> iterable = Lists.newArrayList("a");

    CountingIterable iterable = new CountingIterable();
    List<String> list = ImmutableList.copyOf(iterable);
    assertEquals(asList("a", "b", "a"), list);
  }

  public void testCopyOf_plainIterable_iteratesOnce() {
    CountingIterable iterable = new CountingIterable();
    ImmutableList<String> unused = ImmutableList.copyOf(iterable);
    assertEquals(1, iterable.count);
  }

    protected int index = 0;

    /**
     * for each構文で使用するために配列をラップした{@link Iterable}を返します。
     *
     * @param <T>
     *            列挙する要素の型
     * @param items
     *            イテレートする要素の並び。{@literal null}であってはいけません
     * @return 配列をラップした{@link Iterable}
     */
    public static <T> Iterable<T> iterable(final T... items) {
        assertArgumentNotNull("items", items);

    assertStatsApproxEqual(MANY_VALUES_STATS_ITERABLE, manyValuesAccumulator.xStats());
    assertStatsApproxEqual(
        MANY_VALUES_STATS_ITERABLE, manyValuesAccumulatorByAddAllPartitionedPairedStats.xStats());
  }

  public void testYStats() {
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulator.yStats());
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulatorByAddAllEmptyPairedStats.yStats());

    assertStatsApproxEqual(MANY_VALUES_STATS_ITERABLE, manyValuesAccumulator.xStats());
    assertStatsApproxEqual(
        MANY_VALUES_STATS_ITERABLE, manyValuesAccumulatorByAddAllPartitionedPairedStats.xStats());
  }

  public void testYStats() {
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulator.yStats());
    assertStatsApproxEqual(EMPTY_STATS_ITERABLE, emptyAccumulatorByAddAllEmptyPairedStats.yStats());

  }

  private static <T> List<T> defensiveCopy(T... array) {
    return defensiveCopy(Arrays.asList(array));
  }

  static <T> List<T> defensiveCopy(Iterable<T> iterable) {
    ArrayList<T> list = new ArrayList<>();
    for (T element : iterable) {
      list.add(checkNotNull(element));
    }
    return list;
  }

    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();

    assertEquals(1, iterable.count);
  }

  public void testCopyOf_hashMultiset() {
    Multiset<String> iterable = HashMultiset.create(asList("a", "b", "a"));
    Multiset<String> multiset = ImmutableMultiset.copyOf(iterable);
    assertEquals(HashMultiset.create(asList("a", "b", "a")), multiset);
  }

  public void testCopyOf_treeMultiset() {
    Multiset<String> iterable = TreeMultiset.create(asList("a", "b", "a"));

    @SuppressWarnings("unchecked")
    @Override
    public Entry<String, Integer>[] createArray(int length) {
      return (Entry<String, Integer>[]) new Entry<?, ?>[length];
    }

    @Override
    public Iterable<Entry<String, Integer>> order(List<Entry<String, Integer>> insertionOrder) {
      return insertionOrder;
    }

    @Override
    public List<Entry<String, Integer>> create(Object... elements) {

   * EnumMultiset#create(Iterable)}, this method does not produce an exception on an empty iterable.
   *
   * @since 14.0
   */
  public static <E extends Enum<E>> EnumMultiset<E> create(Iterable<E> elements, Class<E> type) {
    EnumMultiset<E> result = create(type);
    Iterables.addAll(result, elements);
    return result;
  }

  private transient Class<E> type;