// For datasets of many double values created from an iterable, we test many combinations of
    // finite and non-finite values:
    for (ManyValues values : ALL_MANY_VALUES) {
      StatsAccumulator accumulator = new StatsAccumulator();
      StatsAccumulator accumulatorByAddAllStats = new StatsAccumulator();
      accumulator.addAll(values.asIterable());
      for (double value : values.asIterable()) {

      synchronized (mutex) {
        return delegate().put(key, value);
      }
    }

    @Override
    public boolean putAll(@ParametricNullness K key, Iterable<? extends V> values) {
      synchronized (mutex) {
        return delegate().putAll(key, values);
      }
    }

    @Override
    public boolean putAll(Multimap<? extends K, ? extends V> multimap) {

      synchronized (mutex) {
        return delegate().put(key, value);
      }
    }

    @Override
    public boolean putAll(@ParametricNullness K key, Iterable<? extends V> values) {
      synchronized (mutex) {
        return delegate().putAll(key, values);
      }
    }

    @Override
    public boolean putAll(Multimap<? extends K, ? extends V> multimap) {

    assertEquals(0, emptyConcat.size());
  }

  public void testConcat_infiniteIterable() throws IOException {
    ByteSource source = ByteSource.wrap(new byte[] {0, 1, 2, 3});
    Iterable<ByteSource> cycle = Iterables.cycle(ImmutableList.of(source));
    ByteSource concatenated = ByteSource.concat(cycle);

    byte[] expected = {0, 1, 2, 3, 0, 1, 2, 3};
    assertArrayEquals(expected, concatenated.slice(0, 8).read());

  }

  /**
   * Returns {@code true} if every element in {@code values} is {@linkplain #contains contained} in
   * this range.
   */
  public boolean containsAll(Iterable<? extends C> values) {
    if (Iterables.isEmpty(values)) {
      return true;
    }

    // this optimizes testing equality of two range-backed sets
    if (values instanceof SortedSet) {

    cutsToTest.add(Cut.<Integer>belowAll());
    CUTS_TO_TEST = ImmutableList.copyOf(cutsToTest);
  }

  private void testRangesByLowerBounds(
      TreeRangeSet<Integer> rangeSet, Iterable<Range<Integer>> expectedRanges) {
    NavigableMap<Cut<Integer>, Range<Integer>> expectedRangesByLowerBound = Maps.newTreeMap();
    for (Range<Integer> range : expectedRanges) {

    assertTrue(emptyConcat.isEmpty());
  }

  public void testConcat_infiniteIterable() throws IOException {
    CharSource source = CharSource.wrap("abcd");
    Iterable<CharSource> cycle = Iterables.cycle(ImmutableList.of(source));
    CharSource concatenated = CharSource.concat(cycle);

    String expected = "abcdabcd";

  protected <E extends Comparable<? super E>> Set<E> copyOf(Collection<? extends E> elements) {
    return ImmutableSet.copyOf(elements);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> copyOf(Iterable<? extends E> elements) {
    return ImmutableSet.copyOf(elements);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> copyOf(Iterator<? extends E> elements) {

  }

  /**
   * Returns {@code true} if every element in {@code values} is {@linkplain #contains contained} in
   * this range.
   */
  public boolean containsAll(Iterable<? extends C> values) {
    if (Iterables.isEmpty(values)) {
      return true;
    }

    // this optimizes testing equality of two range-backed sets
    if (values instanceof SortedSet) {

   * {@link Collections#frequency} (which would presumably perform more poorly).
   *
   * <p><b>Note:</b> the utility method {@link Iterables#frequency} generalizes this operation; it
   * correctly delegates to this method when dealing with a multiset, but it can also accept any
   * other iterable type.
   *
   * @param element the element to count occurrences of