"SelfEquals", // TODO(cpovirk): Consider using EqualsTester from Guava.
    "UndefinedEquals", // Comparisons of an object to itself *are* defined.
  })
  public void testEquals_self() {
    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  // Comparisons to null *are* defined.
  @SuppressWarnings("UndefinedEquals")
  public void testEquals_null() {
    // noinspection ObjectEqualsNull

    "SelfEquals", // TODO(cpovirk): Consider using EqualsTester from Guava.
    "UndefinedEquals", // Comparisons of an object to itself *are* defined.
  })
  public void testEquals_self() {
    assertTrue("An Object should be equal to itself.", collection.equals(collection));
  }

  // Comparisons to null *are* defined.
  @SuppressWarnings("UndefinedEquals")
  public void testEquals_null() {
    // noinspection ObjectEqualsNull

   * Accordingly, our testing framework adds it only when testing an implementation of List, Set, or
   * Multiset.
   */
  @SuppressWarnings("UndefinedEquals")
  public void testReserialize() {
    assertEquals(SerializableTester.reserialize(actualContents()), actualContents());
  }

        }

        @Override
        /*
         * For discussion of equality in Multimap value collections, see the suppression for
         * UndefinedEquals in AbstractMapBasedMultimap.
         */
        @SuppressWarnings("UndefinedEquals")
        public boolean remove(@Nullable Object o) {
          if (o instanceof Collection) {
            Collection<?> c = (Collection<?>) o;

  public void testClearUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> multimap().clear());
  }

  // Empty multimaps *do* have defined equals semantics.
  @SuppressWarnings("UndefinedEquals")
  private void assertCleared() {
    assertEquals(0, multimap().size());
    assertEmpty(multimap());
    assertEquals(multimap(), getSubjectGenerator().create());
    assertEmpty(multimap().entries());

        }

        @Override
        /*
         * For discussion of equality in Multimap value collections, see the suppression for
         * UndefinedEquals in AbstractMapBasedMultimap.
         */
        @SuppressWarnings("UndefinedEquals")
        public boolean remove(@Nullable Object o) {
          if (o instanceof Collection) {
            Collection<?> c = (Collection<?>) o;

   * implement equals() (as with ListMultimap or SetMultimap, as opposed to a QueueMultimap or
   * something), our equality check is value-based.
   */
  @SuppressWarnings("UndefinedEquals")
  public void testRetainAllPropagatesToMultimap() {
    multimap().entries().retainAll(singleton(mapEntry(k0(), v0())));
    assertEquals(getSubjectGenerator().create(mapEntry(k0(), v0())), multimap());

  public void testClearUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> multimap().clear());
  }

  // Empty multimaps *do* have defined equals semantics.
  @SuppressWarnings("UndefinedEquals")
  private void assertCleared() {
    assertEquals(0, multimap().size());
    assertEmpty(multimap());
    assertEquals(multimap(), getSubjectGenerator().create());
    assertEmpty(multimap().entries());

        () -> multimap().putAll(getSubjectGenerator().create(mapEntry(k3(), v3()))));
  }

  @MapFeature.Require(SUPPORTS_PUT)
  // Empty multimaps *do* have defined equals semantics.
  @SuppressWarnings("UndefinedEquals")
  public void testPutAllIntoEmpty() {
    Multimap<K, V> target = getSubjectGenerator().create();
    assertEquals(!multimap().isEmpty(), target.putAll(multimap()));
    assertEquals(multimap(), target);
  }

  @Override
  public Collection<V> values() {
    return delegate().values();
  }

  @Override
  // A forwarding implementation can't do any better than the underlying object.
  @SuppressWarnings("UndefinedEquals")
  public boolean equals(@Nullable Object object) {
    return object == this || delegate().equals(object);
  }

  @Override
  public int hashCode() {
    return delegate().hashCode();
  }