.test();
  }

  public void testPairwiseEquivalent_equals() {
    new EqualsTester()
        .addEqualityGroup(Equivalence.equals().pairwise(), Equivalence.equals().pairwise())
        .addEqualityGroup(Equivalence.identity().pairwise())
        .testEquals();
  }

  private enum LengthFunction implements Function<String, Integer> {
    INSTANCE;

    @Override
    public Integer apply(String input) {

        toImmutableEnumMap(Entry::getKey, Entry::getValue);
    Equivalence<ImmutableMap<AnEnum, Integer>> equivalence =
        Equivalence.equals().<Entry<AnEnum, Integer>>pairwise().onResultOf(ImmutableMap::entrySet);
    CollectorTester.of(collector, equivalence)
        .expectCollects(
            ImmutableMap.of(AnEnum.A, 1, AnEnum.C, 2, AnEnum.E, 3),
            mapEntry(AnEnum.A, 1),

    return false;
  }

  @Override
  public int hashCode() {
    return elementEquivalence.hashCode() ^ 0x46a3eb07;
  }

  @Override
  public String toString() {
    return elementEquivalence + ".pairwise()";
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;

import java.io.Serializable;
import java.util.Comparator;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

/** An ordering which sorts iterables by comparing corresponding elements pairwise. */
@GwtCompatible
final class LexicographicalOrdering<T extends @Nullable Object> extends Ordering<Iterable<T>>
    implements Serializable {
  final Comparator<? super T> elementOrder;

import java.io.Serializable;
import java.util.Comparator;
import java.util.Iterator;
import org.jspecify.annotations.Nullable;

/** An ordering which sorts iterables by comparing corresponding elements pairwise. */
@GwtCompatible
final class LexicographicalOrdering<T extends @Nullable Object> extends Ordering<Iterable<T>>
    implements Serializable {
  final Comparator<? super T> elementOrder;

    return false;
  }

  @Override
  public int hashCode() {
    return elementEquivalence.hashCode() ^ 0x46a3eb07;
  }

  @Override
  public String toString() {
    return elementEquivalence + ".pairwise()";
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 1;

 * @author Louis Wasserman
 */
@GwtCompatible
public final class Comparators {
  private Comparators() {}

  /**
   * Returns a new comparator which sorts iterables by comparing corresponding elements pairwise
   * until a nonzero result is found; imposes "dictionary order." If the end of one iterable is
   * reached, but not the other, the shorter iterable is considered to be less than the longer one.

        toImmutableSortedMap(Entry::getKey, Entry::getValue, Integer::sum);
    Equivalence<ImmutableMap<String, Integer>> equivalence =
        Equivalence.equals().<Entry<String, Integer>>pairwise().onResultOf(ImmutableMap::entrySet);
    CollectorTester.of(collector, equivalence)
        .expectCollects(
            ImmutableSortedMap.of("one", 1, "three", 3, "two", 4),
            mapEntry("one", 1),

 * @author Louis Wasserman
 */
@GwtCompatible
public final class Comparators {
  private Comparators() {}

  /**
   * Returns a new comparator which sorts iterables by comparing corresponding elements pairwise
   * until a nonzero result is found; imposes "dictionary order." If the end of one iterable is
   * reached, but not the other, the shorter iterable is considered to be less than the longer one.

   *
   * <p>The returned object is serializable if this object is serializable.
   *
   * @since 10.0
   */
  public final <S extends @Nullable T> Equivalence<Iterable<S>> pairwise() {
    // Ideally, the returned equivalence would support Iterable<? extends T>. However,
    // the need for this is so rare that it's not worth making callers deal with the ugly wildcard.