* List<String> actualElements =
 *     Collections.unmodifiableList(
 *         Arrays.asList("a", "b", "c", "d", "e"));
 * IteratorTester<String> iteratorTester =
 *     new IteratorTester<String>(
 *         6,
 *         IteratorFeature.UNMODIFIABLE,
 *         expectedElements,
 *         IteratorTester.KnownOrder.KNOWN_ORDER) {
 *       @Override
 *       protected Iterator<String> newTargetIterator() {

 * List<String> actualElements =
 *     Collections.unmodifiableList(
 *         Arrays.asList("a", "b", "c", "d", "e"));
 * IteratorTester<String> iteratorTester =
 *     new IteratorTester<String>(
 *         6,
 *         IteratorFeature.UNMODIFIABLE,
 *         expectedElements,
 *         IteratorTester.KnownOrder.KNOWN_ORDER) {
 *       @Override
 *       protected Iterator<String> newTargetIterator() {

  @CollectionFeature.Require({SUPPORTS_ITERATOR_REMOVE, KNOWN_ORDER})
  public void testRemovingIteratorKnownOrder() {
    new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {

  public void testIterator_knownOrderRemoveSupported() {
    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
  }

  @CollectionFeature.Require(value = KNOWN_ORDER, absent = SUPPORTS_ITERATOR_REMOVE)
  public void testIterator_knownOrderRemoveUnsupported() {
    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
  }

  @CollectionFeature.Require({SUPPORTS_ITERATOR_REMOVE, KNOWN_ORDER})
  public void testRemovingIteratorKnownOrder() {
    new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {

@GwtCompatible
@NullMarked
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

@GwtCompatible
@NullMarked
public class AbstractSequentialIteratorTest extends TestCase {
  @GwtIncompatible // Too slow
  public void testDoublerExhaustive() {
    new IteratorTester<Integer>(
        3, UNMODIFIABLE, ImmutableList.of(1, 2), IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<Integer> newTargetIterator() {
        return newDoubler(1, 2);
      }
    }.test();
  }

import java.util.ListIterator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A utility similar to {@link IteratorTester} for testing a {@link ListIterator} against a known
 * good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code

  // mode.
  static int listListIteratorTesterNumIterations() {
    // TODO(hhchan): It's 4 in java.  Figure out why even 3 is too slow in prod mode.
    return 2;
  }

  // Use fewer steps in the IteratorTester in CollectionIteratorTester because it's slow in prod
  // mode.
  static int collectionIteratorTesterNumIterations() {
    return 3;
  }

  // TODO: Consolidate different copies in one single place.

import java.util.ListIterator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * A utility similar to {@link IteratorTester} for testing a {@link ListIterator} against a known
 * good reference implementation. As with {@code IteratorTester}, a concrete subclass must provide
 * target iterators on demand. It also requires three additional constructor parameters: {@code