public void testCopyOf_map_empty() {
    Map<Class<?>, Object> in = emptyMap();
    ClassToInstanceMap<Object> map = ImmutableClassToInstanceMap.copyOf(in);
    assertTrue(map.isEmpty());
    assertThat(map).isSameInstanceAs(ImmutableClassToInstanceMap.of());
    assertThat(ImmutableClassToInstanceMap.copyOf(map)).isSameInstanceAs(map);
  }

  public void testOf_zero() {
    assertTrue(ImmutableClassToInstanceMap.of().isEmpty());
  }

  }

  public void testCopyOf_arrayContainingOnlyNull() {
    @Nullable String[] array = new @Nullable String[] {null};
    assertThrows(NullPointerException.class, () -> ImmutableList.copyOf((String[]) array));
  }

  public void testCopyOf_collection_empty() {
    Collection<String> c = MinimalCollection.of();
    List<String> list = ImmutableList.copyOf(c);

      return ImmutableSortedSet.copyOf(elements);
    }
  }

  public static class ImmutableSortedSetHeadsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("zzz");
      return ImmutableSortedSet.copyOf(list).headSet("zzy");
    }
  }

  protected abstract <E extends Comparable<? super E>> Set<E> copyOf(E[] elements);

  protected abstract <E extends Comparable<? super E>> Set<E> copyOf(
      Collection<? extends E> elements);

  protected abstract <E extends Comparable<? super E>> Set<E> copyOf(
      Iterable<? extends E> elements);

  protected abstract <E extends Comparable<? super E>> Set<E> copyOf(
      Iterator<? extends E> elements);

        ImmutableBiMap.copyOf(Collections.<String, Integer>emptyMap());
    assertEquals(Collections.<String, Integer>emptyMap(), copy);
    assertThat(ImmutableBiMap.copyOf(copy)).isSameInstanceAs(copy);
    assertThat(copy).isSameInstanceAs(ImmutableBiMap.of());
  }

  public void testCopyOfSingletonMap() {
    ImmutableBiMap<String, Integer> copy = ImmutableBiMap.copyOf(singletonMap("one", 1));

   *     ImmutableSortedMultiset#copyOf(Comparable[])}.</b>
   */
  @DoNotCall("Elements must be Comparable. (Or, pass a Comparator to orderedBy or copyOf.)")
  @Deprecated
  // The usage of "Z" here works around bugs in Javadoc (JDK-8318093) and JDiff.
  public static <Z> ImmutableSortedMultiset<Z> copyOf(Z[] elements) {
    throw new UnsupportedOperationException();
  }

    ImmutableList<Cell<R, C, V>> cellList = ImmutableList.copyOf(cells);
    for (Cell<R, C, V> cell : cells) {
      rowSpaceBuilder.add(cell.getRowKey());
      columnSpaceBuilder.add(cell.getColumnKey());
    }

    ImmutableSet<R> rowSpace =
        (rowComparator == null)
            ? ImmutableSet.copyOf(rowSpaceBuilder)
            : ImmutableSet.copyOf(ImmutableList.sortedCopyOf(rowComparator, rowSpaceBuilder));

   * is unnecessary; for example, {@code copyOf(copyOf(anArrayList))} should copy the data only
   * once. This reduces the expense of habitually making defensive copies at API boundaries.
   * However, the precise conditions for skipping the copy operation are undefined.
   *
   * @throws NullPointerException if any of {@code elements} is null
   */
  public static <E> ImmutableSet<E> copyOf(Iterable<? extends E> elements) {

    String[] array = new String[0];
    Multiset<String> multiset = ImmutableMultiset.copyOf(array);
    assertTrue(multiset.isEmpty());
  }

  public void testCreation_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    Multiset<String> multiset = ImmutableMultiset.copyOf(array);
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }

    String[] array = new String[0];
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(array);
    assertTrue(multiset.isEmpty());
  }

  public void testCreation_arrayOfOneElement() {
    String[] array = new String[] {"a"};
    Multiset<String> multiset = ImmutableSortedMultiset.copyOf(array);
    assertEquals(HashMultiset.create(asList("a")), multiset);
  }