com.google.common.base.Optional.absent(),
        generator.generateFresh(new TypeToken<com.google.common.base.Optional<String>>() {}));
    assertEquals(
        com.google.common.base.Optional.of("2"),
        generator.generateFresh(new TypeToken<com.google.common.base.Optional<String>>() {}));
    // Test that the first generated instance for different cgcb.Optional<T> is always absent().

        expectedHashCode,
        getMap().hashCode());
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testHashCode_containingNullKey() {
    Entry<K, V> entryWithNull = entry(null, v3());
    runEntryWithNullTest(entryWithNull);
  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @MapFeature.Require(ALLOWS_NULL_VALUES)

  public void testPollFirst() {
    assertEquals(a, navigableSet.pollFirst());
    assertEquals(values.subList(1, values.size()), copyToList(navigableSet));
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  public void testPollFirstUnsupported() {
    assertThrows(UnsupportedOperationException.class, () -> navigableSet.pollFirst());
  }

  @CollectionSize.Require(SEVERAL)

  // Negative oldCount.

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSetCountConditional_negativeOldCount_addSupported() {
    assertSetCountNegativeOldCount();
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  public void testSetCountConditional_negativeOldCount_addUnsupported() {
    try {
      assertSetCountNegativeOldCount();
    } catch (UnsupportedOperationException tolerated) {
    }
  }

   * opening the data stream.
   *
   * <p>The default implementation returns {@link Optional#absent}. Some sources, such as a {@code
   * CharSequence}, may return a non-absent value. Note that in such cases, it is <i>possible</i>
   * that this method will return a different number of chars than would be returned by reading all
   * of the chars.
   *

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class CollectionSpliteratorTester<E> extends AbstractCollectionTester<E> {

  @CollectionFeature.Require(absent = KNOWN_ORDER)
  public void testSpliteratorUnknownOrder() {
    SpliteratorTester.of(collection::spliterator).expect(getSampleElements());
  }

  @CollectionFeature.Require(KNOWN_ORDER)

        assertGet(key, expectedValues);
        assertEquals(value, values.get(values.size() - 1));
      }
    }
  }

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

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

      K k = entry.getKey();

  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    public abstract MapFeature[] value() default {};

    public abstract MapFeature[] absent() default {};
  }

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class ListRetainAllTester<E> extends AbstractListTester<E> {
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRetainAll_duplicatesKept() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);
    assertFalse(

  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testElementSetReflectsRemove() {
    Set<E> elementSet = getMultiset().elementSet();
    assertTrue(elementSet.contains(e0()));
    getMultiset().removeAll(singleton(e0()));
    assertFalse(elementSet.contains(e0()));
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)