.build();
    assertEquals(HashMultiset.create(asList("b", "b", "b")), multiset);
  }

  public void testBuilderSetCountThenAdd() {
    ImmutableSortedMultiset<String> multiset =
        ImmutableSortedMultiset.<String>naturalOrder()
            .add("a")
            .setCount("a", 2)
            .setCount("b", 3)
            .setCount("a", 1)
            .add("a")
            .build();

    }
    int[] result = new int[1]; // used as a mutable int reference to hold result
    AvlNode<E> newRoot = root.setCount(comparator(), element, count, result);
    rootReference.checkAndSet(root, newRoot);
    return result[0];
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
    checkNonnegative(newCount, "newCount");

  }

  /** Call the {@code setCount()} method under test, and check its return value. */
  abstract void setCountCheckReturnValue(E element, int count);

  /**
   * Call the {@code setCount()} method under test, but do not check its return value. Callers
   * should use this method over {@link #setCountCheckReturnValue(Object, int)} when they expect
   * {@code setCount()} to throw an exception, as checking the return value could produce an

  }

  /** Call the {@code setCount()} method under test, and check its return value. */
  abstract void setCountCheckReturnValue(E element, int count);

  /**
   * Call the {@code setCount()} method under test, but do not check its return value. Callers
   * should use this method over {@link #setCountCheckReturnValue(Object, int)} when they expect
   * {@code setCount()} to throw an exception, as checking the return value could produce an

     * @throws NullPointerException if {@code element} is null
     * @throws IllegalArgumentException if {@code count} is negative
     */
    @CanIgnoreReturnValue
    public Builder<E> setCount(E element, int count) {
      contents.setCount(checkNotNull(element), count);
      return this;
    }

    /**
     * Adds each element of {@code elements} to the {@code ImmutableMultiset}.
     *

    @Override
    public void clear() {
      throw new UnsupportedOperationException();
    }

    @Override
    public int setCount(@ParametricNullness E element, int count) {
      throw new UnsupportedOperationException();
    }

    @Override
    public boolean setCount(@ParametricNullness E element, int oldCount, int newCount) {
      throw new UnsupportedOperationException();
    }

  }

  public void testBuilderSetCount() {
    ImmutableSortedMultiset<String> multiset =
        ImmutableSortedMultiset.<String>naturalOrder()
            .add("a")
            .setCount("a", 2)
            .setCount("b", 3)
            .build();
    assertEquals(HashMultiset.create(asList("a", "a", "b", "b", "b")), multiset);
  }

  public void testBuilderAddHandlesNullsCorrectly() {

  }

  public void testBuilderSetCount() {
    ImmutableMultiset<String> multiset =
        new ImmutableMultiset.Builder<String>().add("a").setCount("a", 2).setCount("b", 3).build();
    assertEquals(HashMultiset.create(asList("a", "a", "b", "b", "b")), multiset);
  }

  public void testBuilderAddHandlesNullsCorrectly() {

   *
   * @return the count of {@code element} in the multiset before this call
   * @throws IllegalArgumentException if {@code count} is negative
   */
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkNotNull(element);
    checkNonnegative(count, "count");
    while (true) {
      AtomicInteger existingCounter = Maps.safeGet(countMap, element);
      if (existingCounter == null) {

   *
   * @return the count of {@code element} in the multiset before this call
   * @throws IllegalArgumentException if {@code count} is negative
   */
  @CanIgnoreReturnValue
  @Override
  public int setCount(E element, int count) {
    checkNotNull(element);
    checkNonnegative(count, "count");
    while (true) {
      AtomicInteger existingCounter = Maps.safeGet(countMap, element);
      if (existingCounter == null) {