new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {
        return getSubjectGenerator().create(e0(), e1(), e1(), e2()).iterator();
      }
    }.test();
  }

    new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {
        return getSubjectGenerator().create(e0(), e1(), e1(), e2()).iterator();
      }
    }.test();
  }

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

  @Override
  protected <E extends Comparable<? super E>> Set<E> of(E e1, E e2, E e3) {
    return ImmutableSet.of(e1, e2, e3);
  }

  @Override
  protected <E extends Comparable<? super E>> Set<E> of(E e1, E e2, E e3, E e4) {
    return ImmutableSet.of(e1, e2, e3, e4);
  }

  @Override

            }

            return v1.compareTo(v2) > 0 ? e2 : e1;
        }

        if (closerFirst) {
            return depth1 < depth2 ? e1 : e2;
        }

        return depth1 < depth2 ? e2 : e1;
    }

  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;
  private final E e1;
  private final E e2;
  private final E e3;
  private final E e4;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override
  public Iterator<E> iterator() {

            //                                        return
            // e1.getTarget().toString().compareTo(e2.getTarget().toString() );
            //
            //                                    return e2.getPomOrder() - e1.getPomOrder();
            //                                }
            //
            //                                return e2.getDepth() - e1.getDepth();

  }

  /** Returns an immutable sorted set containing a single element. */
  public static <E extends Comparable<? super E>> ImmutableSortedSet<E> of(E e1) {
    return new RegularImmutableSortedSet<>(ImmutableList.of(e1), Ordering.natural());
  }

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.

  public static ImmutableLongArray of(long e0, long e1) {
    return new ImmutableLongArray(new long[] {e0, e1});
  }

  /** Returns an immutable array containing the given values, in order. */
  public static ImmutableLongArray of(long e0, long e1, long e2) {
    return new ImmutableLongArray(new long[] {e0, e1, e2});
  }

  /** Returns an immutable array containing the given values, in order. */

  public static ImmutableIntArray of(int e0, int e1) {
    return new ImmutableIntArray(new int[] {e0, e1});
  }

  /** Returns an immutable array containing the given values, in order. */
  public static ImmutableIntArray of(int e0, int e1, int e2) {
    return new ImmutableIntArray(new int[] {e0, e1, e2});
  }

  /** Returns an immutable array containing the given values, in order. */

  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;
  private final E e1;
  private final E e2;
  private final E e3;
  private final E e4;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override
  public Iterator<E> iterator() {