private abstract static class EmptyIteratorTester extends IteratorTester<Integer> {
    protected EmptyIteratorTester() {
      super(3, MODIFIABLE, Collections.<Integer>emptySet(), IteratorTester.KnownOrder.KNOWN_ORDER);
    }
  }

  @GwtIncompatible // Only used by @GwtIncompatible code
  private abstract static class SingletonIteratorTester extends IteratorTester<Integer> {
    protected SingletonIteratorTester() {

    checkFooBarBazList(list);
    SerializableTester.reserializeAndAssert(list);
    assertTrue(list instanceof RandomAccess);

    new IteratorTester<String>(
        5, UNMODIFIABLE, asList("foo", "bar", "baz"), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<String> newTargetIterator() {
        return Lists.asList("foo", new String[] {"bar", "baz"}).iterator();
      }

    assertEquals("[a, b, c, d, e, f, g]", set.toString());
  }

  @GwtIncompatible // slow (~40s)
  public void testIterator_oneElement() {
    new IteratorTester<String>(
        5, UNMODIFIABLE, Collections.singleton("a"), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<String> newTargetIterator() {
        return of("a").iterator();
      }
    }.test();
  }

    assertEquals("[a, b, c, d, e, f, g]", set.toString());
  }

  @GwtIncompatible // slow (~40s)
  public void testIterator_oneElement() {
    new IteratorTester<String>(
        5, UNMODIFIABLE, Collections.singleton("a"), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<String> newTargetIterator() {
        return of("a").iterator();
      }
    }.test();
  }

@ElementTypesAreNonnullByDefault
public class PeekingIteratorTest extends TestCase {

  /**
   * Version of {@link IteratorTester} that compares an iterator over a given collection of elements
   * (used as the reference iterator) against a {@code PeekingIterator} that *wraps* such an
   * iterator (used as the target iterator).
   *
   * <p>This IteratorTester makes copies of the master so that it can later verify that {@link

  private abstract static class EmptyIteratorTester extends IteratorTester<Integer> {
    protected EmptyIteratorTester() {
      super(3, MODIFIABLE, Collections.<Integer>emptySet(), IteratorTester.KnownOrder.KNOWN_ORDER);
    }
  }

  @GwtIncompatible // Only used by @GwtIncompatible code
  private abstract static class SingletonIteratorTester extends IteratorTester<Integer> {
    protected SingletonIteratorTester() {

 * @author Kevin Bourrillion
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class SetsTest extends TestCase {

  private static final IteratorTester.KnownOrder KNOWN_ORDER =
      IteratorTester.KnownOrder.KNOWN_ORDER;

  private static final Collection<Integer> EMPTY_COLLECTION = Arrays.<Integer>asList();

  private static final Collection<Integer> SOME_COLLECTION = Arrays.asList(0, 1, 1);

    } catch (UnsupportedOperationException expected) {
    }
  }

  @GwtIncompatible // slow (~35s)
  public void testSkip_iterator() {
    new IteratorTester<Integer>(
        5, MODIFIABLE, newArrayList(2, 3), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<Integer> newTargetIterator() {
        return skip(newLinkedHashSet(asList(1, 2, 3)), 1).iterator();
      }

    checkFooBarBazList(list);
    SerializableTester.reserializeAndAssert(list);
    assertTrue(list instanceof RandomAccess);

    new IteratorTester<String>(
        5, UNMODIFIABLE, asList("foo", "bar", "baz"), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<String> newTargetIterator() {
        return Lists.asList("foo", new String[] {"bar", "baz"}).iterator();
      }

  }

  private <T extends Comparable<T>> void runIterator(final List<T> values, int steps)
      throws Exception {
    IteratorTester<T> tester =
        new IteratorTester<T>(
            steps,
            IteratorFeature.MODIFIABLE,
            Lists.newLinkedList(values),
            IteratorTester.KnownOrder.UNKNOWN_ORDER) {
          private @Nullable MinMaxPriorityQueue<T> mmHeap;

          @Override