@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class SetHashCodeTester<E> extends AbstractSetTester<E> {
  public void testHashCode() {
    int expectedHashCode = 0;
    for (E element : getSampleElements()) {
      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements.",
        expectedHashCode,

  public void testEqualsTrue() {
    new EqualsTester()
        .addEqualityGroup(multimap(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  public void testEqualsFalse() {
    List<Entry<K, V>> targetEntries = new ArrayList<>(getSampleElements());
    targetEntries.add(mapEntry(k0(), v3()));
    new EqualsTester()
        .addEqualityGroup(multimap())

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MultimapKeySetTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {
  public void testKeySet() {
    for (Entry<K, V> entry : getSampleElements()) {
      assertTrue(multimap().keySet().contains(entry.getKey()));
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testKeySetContainsNullKeyPresent() {

@NullMarked
public interface OneSizeTestContainerGenerator<T, E extends @Nullable Object>
    extends TestSubjectGenerator<T>, TestContainerGenerator<T, E> {
  TestContainerGenerator<T, E> getInnerGenerator();

  Collection<E> getSampleElements(int howMany);

  CollectionSize getCollectionSize();

public class MultisetEqualsTester<E> extends AbstractMultisetTester<E> {
  public void testEqualsSameContents() {
    new EqualsTester()
        .addEqualityGroup(
            getMultiset(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  @CollectionSize.Require(absent = ZERO)
  public void testNotEqualsEmpty() {
    new EqualsTester()
        .addEqualityGroup(getMultiset())

   * that corresponds to the expected elements.
   */

  @CollectionFeature.Require(absent = KNOWN_ORDER)
  public void testStreamToArrayUnknownOrder() {
    assertEqualIgnoringOrder(getSampleElements(), asList(collection.stream().toArray()));
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testStreamToArrayKnownOrder() {
    assertEquals(getOrderedElements(), asList(collection.stream().toArray()));

   * that corresponds to the expected elements.
   */

  @CollectionFeature.Require(absent = KNOWN_ORDER)
  public void testStreamToArrayUnknownOrder() {
    Helpers.assertEqualIgnoringOrder(getSampleElements(), asList(collection.stream().toArray()));
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testStreamToArrayKnownOrder() {
    assertEquals(getOrderedElements(), asList(collection.stream().toArray()));

    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
  }

  @CollectionFeature.Require(absent = {KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
  public void testIterator_unknownOrderRemoveUnsupported() {
    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
  }

  private void runIteratorTest(

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MultimapValuesTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {
  public void testValues() {
    List<V> expected = new ArrayList<>();
    for (Entry<K, V> entry : getSampleElements()) {
      expected.add(entry.getValue());
    }
    assertEqualIgnoringOrder(expected, multimap().values());
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testValuesInOrder() {

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class MultimapKeySetTester<K, V> extends AbstractMultimapTester<K, V, Multimap<K, V>> {
  public void testKeySet() {
    for (Entry<K, V> entry : getSampleElements()) {
      assertTrue(multimap().keySet().contains(entry.getKey()));
    }
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testKeySetContainsNullKeyPresent() {