* </ol>
   *
   * @param collection the presumed-immutable collection
   * @param sampleElement an element of the same type as that contained by {@code collection}.
   *     {@code collection} may or may not have {@code sampleElement} as a member.
   */
  public static <E extends @Nullable Object> void assertCollectionIsUnmodifiable(
      Collection<E> collection, E sampleElement) {
    Collection<E> siblingCollection = new ArrayList<>();

   * words, for the default {@code expectContents()} implementation, the number of occurrences of
   * each given element has increased by one since the test collection was created, and the number
   * of occurrences of all other elements has not changed.
   *
   * <p>Note: This means that a test like the following will fail if {@code collection} is a {@code
   * Set}:
   *
   * <pre>

  }

  private static <E> ImmutableList<E> copyFromCollection(Collection<? extends E> collection) {
    Object[] elements = collection.toArray();
    switch (elements.length) {
      case 0:
        return of();
      case 1:
        @SuppressWarnings("unchecked") // safe because it came from `collection`
        E element = (E) elements[0];
        return of(element);
      default:

  }

  public void testCopyOf_collectionContainingNull() {
    Collection<@Nullable String> c = MinimalCollection.of("a", null, "b");
    assertThrows(NullPointerException.class, () -> copyOf((Collection<String>) c));
  }

  enum TestEnum {
    A,
    B,
    C,
    D
  }

  public void testCopyOf_collection_enumSet() {
    Collection<TestEnum> c = EnumSet.of(TestEnum.A, TestEnum.B, TestEnum.D);

 * limitations under the License.
 */

/**
 * Collection interfaces and implementations, and other utilities for collections. This package is a
 * part of the open-source <a href="https://github.com/google/guava">Guava</a> library.
 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional

 * limitations under the License.
 */

/**
 * Collection interfaces and implementations, and other utilities for collections. This package is a
 * part of the open-source <a href="https://github.com/google/guava">Guava</a> library.
 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional

    return unmodifiableList((List<E>) collection);
  }

  @Override
  Collection<V> wrapCollection(@ParametricNullness K key, Collection<V> collection) {
    return wrapList(key, (List<V>) collection, null);
  }

  // Following Javadoc copied from ListMultimap.

  /**
   * {@inheritDoc}
   *
   * <p>Because the values for a given key may have duplicates and follow the insertion ordering,

    return suite;
  }

  protected Collection<Method> suppressForArrayDeque() {
    return emptySet();
  }

  protected Collection<Method> suppressForLinkedList() {
    return emptySet();
  }

  protected Collection<Method> suppressForArrayBlockingQueue() {
    return emptySet();
  }

  protected Collection<Method> suppressForConcurrentLinkedQueue() {
    return emptySet();
  }

      K key = entry.getKey();
      V value = entry.getValue();
      Collection<V> collection = multimap().get(key);
      assertNotNull(collection);
      Collection<V> expectedCollection = copyToList(collection);

      multimap().remove(key, value);
      expectedCollection.remove(value);

      assertEqualIgnoringOrder(expectedCollection, collection);
      assertEquals(!expectedCollection.isEmpty(), multimap().containsKey(key));

    return emptySet();
  }

  private Collection<Method> suppressForEmptySortedMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForSingletonMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForHashMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForHashtable() {