assertEquals(0, getMultiset().remove(null, 2));
  }

  @CollectionFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_QUERIES)
  public void testRemove_nullForbidden() {
    assertThrows(NullPointerException.class, () -> getMultiset().remove(null, 2));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllIgnoresCount() {
    initThreeCopies();

    assertEquals(0, getMultiset().remove(null, 2));
  }

  @CollectionFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_QUERIES)
  public void testRemove_nullForbidden() {
    assertThrows(NullPointerException.class, () -> getMultiset().remove(null, 2));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllIgnoresCount() {
    initThreeCopies();

   * set is serializable.
   *
   * @param elements the elements that the set should contain
   * @return a new thread-safe set containing those elements (minus duplicates)
   * @throws NullPointerException if {@code elements} or any of its contents is null
   * @since 15.0
   */
  public static <E> Set<E> newConcurrentHashSet(Iterable<? extends E> elements) {
    Set<E> set = newConcurrentHashSet();

  public void testGetNullAbsent() {
    assertEmpty(multimap().get(null));
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEY_QUERIES)
  public void testGetNullForbidden() {
    assertThrows(NullPointerException.class, () -> multimap().get(null));
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testGetWithNullValue() {
    initMultimapWithNullValue();

  /**
   * A collector that converts a stream of zero or one elements to an {@code Optional}.
   *
   * @throws IllegalArgumentException if the stream consists of two or more elements.
   * @throws NullPointerException if any element in the stream is {@code null}.
   * @return {@code Optional.of(onlyElement)} if the stream has exactly one element (must not be
   *     {@code null}) and returns {@code Optional.empty()} if it has none.
   */

    this.tester = EquivalenceTester.of(equivalenceMock);
  }

  /** Test null reference yields error */
  public void testOf_nullPointerException() {
    assertThrows(NullPointerException.class, () -> EquivalenceTester.of(null));
  }

  public void testTest_noData() {
    tester.test();
  }

  public void testTest() {
    Object group1Item1 = new TestObject(1, 1);

    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testSetFailureNull() throws Exception {
    assertThrows(NullPointerException.class, () -> future.setException(null));
    assertFalse(future.isDone());
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

    this.tester = EquivalenceTester.of(equivalenceMock);
  }

  /** Test null reference yields error */
  public void testOf_nullPointerException() {
    assertThrows(NullPointerException.class, () -> EquivalenceTester.of(null));
  }

  public void testTest_noData() {
    tester.test();
  }

  public void testTest() {
    Object group1Item1 = new TestObject(1, 1);

  @CollectionSize.Require(absent = ZERO)
  public void testSetValueWithNullValuesAbsent() {
    for (Entry<K, V> entry : getMap().entrySet()) {
      assertThrows(NullPointerException.class, () -> entry.setValue(null));
      break;
    }
    expectUnchanged();
  }

  @J2ktIncompatible
  @GwtIncompatible // reflection

    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }

  public void testSetFailureNull() throws Exception {
    assertThrows(NullPointerException.class, () -> future.setException(null));
    assertFalse(future.isDone());
    assertTrue(future.setException(new Exception("failure")));
    tester.testFailedFuture("failure");
  }