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(

      Table<String, Integer, Character> table, String[] elements) {
    for (String row : elements) {
      table.put(row, 1, 'a');
      table.put(row, 2, 'b');
    }
  }

  private static void populateForColumnKeySet(
      Table<Integer, String, Character> table, String[] elements) {
    for (String column : elements) {
      table.put(1, column, 'a');
      table.put(2, column, 'b');
    }

    @Override
    protected List<String> create(String[] elements) {
      String[] suffix = {"f", "g"};
      String[] all = new String[elements.length + suffix.length];
      arraycopy(elements, 0, all, 0, elements.length);
      arraycopy(suffix, 0, all, elements.length, suffix.length);
      return ImmutableList.copyOf(all).subList(0, elements.length);
    }
  }

   * which the elements appear in the given collection.
   *
   * @param elements the elements, all of the same {@code enum} type, that the set should contain
   * @return an immutable set containing those elements, minus duplicates
   */
  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(Iterable<E> elements) {
    if (elements instanceof ImmutableEnumSet) {

    multimap.put(2, "foo");
    for (String element : elements) {
      multimap.put(3, element);
    }
  }

  static void populateMultimapForKeySet(Multimap<String, Integer> multimap, String[] elements) {
    for (String element : elements) {
      multimap.put(element, 2);
      multimap.put(element, 3);
    }
  }

              @Override
              public Collection<@Nullable String> create(@Nullable String[] elements) {
                List<@Nullable String> list = new ArrayList<>();
                for (String element : elements) {
                  list.add((element == null) ? null : "q" + element);
                }
                return Collections2.transform(

    return new Strings();
  }

  @Override
  public List<String> create(Object... elements) {
    String[] array = new String[elements.length];
    int i = 0;
    for (Object e : elements) {
      array[i++] = (String) e;
    }
    return create(array);
  }

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

                  @Override
                  protected Set<String> create(String[] elements) {
                    // Put the sets in different orders for the hell of it
                    return union(
                        new LinkedHashSet<>(asList(elements[0], elements[1], elements[2])),
                        new LinkedHashSet<>(asList(elements[1], elements[0], elements[2])));
                  }
                })

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity
   * as an element is indicated by the presence or absence of {@link #ALLOWS_NULL_VALUES}). From the
   * documentation for {@link Collection}:
   *
   * <blockquote>
   *
   * "Some collection implementations have restrictions on the elements that they may contain. For

  /**
   * Inserts the specified element into this priority queue.
   *
   * @param e the element to add
   * @return {@code true} (as specified by {@link Queue#offer})
   * @throws ClassCastException if the specified element cannot be compared with elements currently
   *     in the priority queue according to the priority queue's ordering
   * @throws NullPointerException if the specified element is null
   */