throw new UnsupportedOperationException();
  }

  @Override
  protected Map<Object, Integer> makePopulatedMap() {
    Colliders colliders = new Colliders();
    return ImmutableMap.of(
        colliders.e0(), 0,
        colliders.e1(), 1,
        colliders.e2(), 2,
        colliders.e3(), 3);
  }

  @Override
  protected Object getKeyNotInPopulatedMap() {
    return new Colliders().e4();
  }

  @Override

  @Override
  protected Map<Integer, UnhashableObject> makePopulatedMap() {
    Unhashables unhashables = new Unhashables();
    return ImmutableMap.of(0, unhashables.e0());
  }

    return ImmutableMap.of();
  }

  @Override
  protected Map<Integer, UnhashableObject> makePopulatedMap() {
    Unhashables unhashables = new Unhashables();
    return ImmutableMap.of(0, unhashables.e0(), 1, unhashables.e1(), 2, unhashables.e2());
  }

  @Override
  protected Integer getKeyNotInPopulatedMap() {
    return 3;
  }

  @Override
  protected UnhashableObject getValueNotInPopulatedMap() {

    return ImmutableMap.of();
  }

  @Override
  protected Map<Integer, UnhashableObject> makePopulatedMap() {
    Unhashables unhashables = new Unhashables();
    return ImmutableMap.of(0, unhashables.e0(), 1, unhashables.e1(), 2, unhashables.e2());
  }

  @Override
  protected Integer getKeyNotInPopulatedMap() {
    return 3;
  }

  @Override
  protected UnhashableObject getValueNotInPopulatedMap() {

   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

  protected final K k0() {
    return e0().getKey();
  }

  protected final V v0() {
    return e0().getValue();
  }

  protected final K k1() {
    return e1().getKey();
  }

  protected final V v1() {
    return e1().getValue();
  }

  @CollectionFeature.Require(absent = REJECTS_DUPLICATES_AT_CREATION)
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);

    expectContents(array);
  }

  @CollectionFeature.Require(absent = REJECTS_DUPLICATES_AT_CREATION)
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);

    expectContents(array);
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedPresent() {
    assertFalse("add(present) should return false", getSet().add(e0()));
    expectUnchanged();
  }

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {

    return generator.create(elements.toArray());
  }

  @Override
  public Collection<E> getSampleElements(int howMany) {
    SampleElements<E> samples = samples();
    List<E> allSampleElements =
        asList(samples.e0(), samples.e1(), samples.e2(), samples.e3(), samples.e4());
    return new ArrayList<>(allSampleElements.subList(0, howMany));
  }

  @Override
  public CollectionSize getCollectionSize() {
    return collectionSize;

    return generator.create(elements.toArray());
  }

  @Override
  public Collection<E> getSampleElements(int howMany) {
    SampleElements<E> samples = samples();
    List<E> allSampleElements =
        asList(samples.e0(), samples.e1(), samples.e2(), samples.e3(), samples.e4());
    return new ArrayList<>(allSampleElements.subList(0, howMany));
  }

  @Override
  public CollectionSize getCollectionSize() {
    return collectionSize;