}

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  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);

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require({SUPPORTS_REMOVE, SUPPORTS_PUT})
  public void testPropagatesRemoveThenAddToMultimap() {
    int oldSize = getNumElements();

    Collection<V> result = multimap().asMap().get(k0());
    assertTrue(result.remove(v0()));

    assertFalse(multimap().containsKey(k0()));
    assertFalse(multimap().containsEntry(k0(), v0()));

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class CollectionSizeTester<E> extends AbstractCollectionTester<E> {
  public void testSize() {
    assertEquals("size():", getNumElements(), collection.size());
  }

    this.implied = copyToSet(implied);
    this.numElements = null;
  }

  @Override
  public Set<Feature<? super Collection>> getImpliedFeatures() {
    return implied;
  }

  public int getNumElements() {
    if (numElements == null) {
      throw new IllegalStateException(
          "A compound CollectionSize doesn't specify a number of elements.");
    }
    return numElements;
  }

    this.implied = copyToSet(implied);
    this.numElements = null;
  }

  @Override
  public Set<Feature<? super Collection>> getImpliedFeatures() {
    return implied;
  }

  public int getNumElements() {
    if (numElements == null) {
      throw new IllegalStateException(
          "A compound CollectionSize doesn't specify a number of elements.");
    }
    return numElements;
  }

  public void testGet_negative() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().get(-1));
  }

  public void testGet_tooLarge() {
    assertThrows(IndexOutOfBoundsException.class, () -> getList().get(getNumElements()));
  }

  @Override
  public E[] createArray(int length) {
    return generator.createArray(length);
  }

  @Override
  public T createTestSubject() {
    Collection<E> elements = getSampleElements(getCollectionSize().getNumElements());
    return generator.create(elements.toArray());
  }

  @Override
  public Collection<E> getSampleElements(int howMany) {
    SampleElements<E> samples = samples();
    List<E> allSampleElements =

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testPutDuplicateValuePreservesSize() {
    assertFalse(multimap().put(k0(), v0()));
    assertEquals(getNumElements(), multimap().size());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {

    return entries;
  }

  private void expectFirstRemoved(Entry<K, V>[] entries) {
    resetMap(entries);

    List<Entry<K, V>> expectedWithDuplicateRemoved = asList(entries).subList(1, getNumElements());
    expectContents(expectedWithDuplicateRemoved);
  }

  /**
   * Returns the {@link Method} instance for {@link #testCreateWithNullKeyUnsupported()} so that

  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  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);