public void testHashCode_containingNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    int expectedHashCode = 0;
    for (E element : elements) {
      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }

    elements.add(null);
    collection = getSubjectGenerator().create(elements.toArray());
    assertEquals(

    }

    @Override
    public boolean add(@ParametricNullness E element) {
      checkArgument(predicate.apply(element));
      return unfiltered.add(element);
    }

    @Override
    public boolean addAll(Collection<? extends E> collection) {
      for (E element : collection) {
        checkArgument(predicate.apply(element));
      }
      return unfiltered.addAll(collection);
    }

        Multiset<String> multiset1 = LinkedHashMultiset.create();
        Multiset<String> multiset2 = LinkedHashMultiset.create();
        multiset1.add("only1");
        multiset2.add("only2");
        for (int i = 0; i < elements.length; i++) {
          multiset1.add(elements[i]);
          multiset2.add(elements[elements.length - 1 - i]);
        }
        if (elements.length > 0) {

  /** Returns an iterable whose iterator returns the given elements in order. */
  public static <E extends @Nullable Object> MinimalIterable<E> of(E... elements) {
    // Make sure to get an unmodifiable iterator
    return new MinimalIterable<>(asList(elements).iterator());
  }

  /**
   * Returns an iterable whose iterator returns the given elements in order. The elements are copied

   * unspecified order.
   *
   * @param elements the elements that the set should contain
   * @return a new {@code CompactHashSet} containing those elements (minus duplicates)
   */
  @SafeVarargs
  public static <E extends @Nullable Object> CompactHashSet<E> create(E... elements) {
    CompactHashSet<E> set = createWithExpectedSize(elements.length);

   *
   * @param elements the collection of elements to be checked for containment in this multiset
   * @return {@code true} if this multiset contains at least one occurrence of each element
   *     contained in {@code elements}
   * @throws NullPointerException if {@code elements} is null
   */
  @Override
  boolean containsAll(Collection<?> elements);

  /**
   * {@inheritDoc}
   *

   *
   * @param elements the collection of elements to be checked for containment in this multiset
   * @return {@code true} if this multiset contains at least one occurrence of each element
   *     contained in {@code elements}
   * @throws NullPointerException if {@code elements} is null
   */
  @Override
  boolean containsAll(Collection<?> elements);

  /**
   * {@inheritDoc}
   *

    assertEquals("Should have removed an element", 2, list.size());
    assertFalse("Second element should be gone", list.contains("B"));
  }

  static class ThrowsAtEndException extends RuntimeException {
    /* nothing */
  }

  /**
   * This Iterator claims to have more elements than the underlying iterable, but when you try to
   * fetch the extra elements, it throws an unchecked exception.
   */

        throw PermittedMetaException.ISE;
      }
    }

    private List<E> getElements() {
      List<E> elements = new ArrayList<>();
      Helpers.addAll(elements, previousElements);
      Helpers.addAll(elements, Helpers.reverse(nextElements));
      return elements;
    }
  }

  public enum KnownOrder {
    KNOWN_ORDER,
    UNKNOWN_ORDER
  }

    return new Unhashables();
  }

  @Override
  public T create(Object... elements) {
    UnhashableObject[] array = createArray(elements.length);
    int i = 0;
    for (Object e : elements) {
      array[i++] = (UnhashableObject) e;
    }
    return create(array);
  }

  /**
   * Creates a new collection containing the given elements; implement this method instead of {@link
   * #create(Object...)}.
   */