* 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();
  }

  public static class ImmutableSetCopyOfGenerator extends TestStringSetGenerator {
    @Override
    protected Set<String> create(String[] elements) {
      return ImmutableSet.copyOf(elements);
    }
  }

  public static class ImmutableSetUnsizedBuilderGenerator extends TestStringSetGenerator {
    @Override
    protected Set<String> create(String[] elements) {
      ImmutableSet.Builder<String> builder = ImmutableSet.builder();

  public static class ImmutableListOfGenerator extends TestStringListGenerator {
    @Override
    protected List<String> create(String[] elements) {
      return ImmutableList.copyOf(elements);
    }
  }

  public static class BuilderAddListGenerator extends TestStringListGenerator {
    @Override
    protected List<String> create(String[] elements) {
      ImmutableList.Builder<String> builder = ImmutableList.<String>builder();

  }

  protected Collection<Method> suppressForCheckedSet() {
    return emptySet();
  }

  protected Collection<Method> suppressForCheckedSortedSet() {
    return emptySet();
  }

  protected Collection<Method> suppressForAbstractSet() {
    return emptySet();
  }

  protected Collection<Method> suppressForConcurrentSkipListSetNatural() {
    return emptySet();
  }

   * 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();
  }

   *     that involve a null element being present.
   */
  protected int getNullLocation() {
    return getNumElements() / 2;
  }

  protected MinimalCollection<E> createDisjointCollection() {
    return MinimalCollection.of(e3(), e4());
  }

  protected MinimalCollection<E> emptyCollection() {
    return MinimalCollection.<E>of();
  }

  protected final E e0() {
    return samples.e0();
  }

  }

  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();
  }

  protected final K k2() {
    return e2().getKey();
  }

    return suite;
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> of() {
    return ImmutableSet.of();
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> of(E e) {
    return ImmutableSet.of(e);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> of(E e1, E e2) {
    return ImmutableSet.of(e1, e2);
  }

  @SuppressWarnings("unchecked")
  protected B self() {
    return (B) this;
  }

  // Test Data

  private @Nullable G subjectGenerator;
  // Gets run before every test.
  private Runnable setUp;
  // Gets run at the conclusion of every test.
  private Runnable tearDown;

  @CanIgnoreReturnValue
  protected B usingGenerator(G subjectGenerator) {

  protected Collection<Method> suppressForSynchronizedNavigableMap() {
    return emptySet();
  }

  protected Collection<Method> suppressForTreeMapNatural() {
    return emptySet();
  }

  protected Collection<Method> suppressForTreeMapWithComparator() {
    return emptySet();
  }

  protected Collection<Method> suppressForUnmodifiableMap() {
    return emptySet();
  }