// the CacheBuilder default).
  private Set<Integer> concurrencyLevels = Sets.newHashSet((Integer) null);
  private Set<Integer> initialCapacities = Sets.newHashSet((Integer) null);
  private Set<Integer> maximumSizes = Sets.newHashSet((Integer) null);
  private Set<DurationSpec> expireAfterWrites = Sets.newHashSet((DurationSpec) null);
  private Set<DurationSpec> expireAfterAccesses = Sets.newHashSet((DurationSpec) null);

    assertEquals("google", keySet.last());
    assertEquals(StringLength.COMPARATOR, keySet.comparator());
    assertEquals(Sets.<@Nullable String>newHashSet(null, "tree"), keySet.headSet("yahoo"));
    assertEquals(Sets.newHashSet("google"), keySet.tailSet("yahoo"));
    assertEquals(Sets.newHashSet("tree"), keySet.subSet("ask", "yahoo"));
  }

  @GwtIncompatible // SerializableTester

  @Beta // TODO: b/288085449 - Remove @Beta after we're sure that Java 8 APIs are safe for Android
  public FakeTicker advance(Duration duration) {
    return advance(duration.toNanos());
  }

  /**
   * Sets the increment applied to the ticker whenever it is queried.
   *
   * <p>The default behavior is to auto increment by zero. i.e: The ticker is left unchanged when
   * queried.
   */

import com.google.common.collect.testing.SampleElements.Enums;
import java.util.Collections;
import java.util.List;
import java.util.Set;

/**
 * An abstract TestSetGenerator for generating sets containing enum values.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestEnumSetGenerator implements TestSetGenerator<AnEnum> {
  @Override

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Strings;
import java.util.List;
import java.util.Set;

/**
 * Create string sets for collection tests.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestStringSetGenerator implements TestSetGenerator<String> {
  @Override

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Ints;
import java.util.List;
import java.util.Set;

/**
 * Create integer sets for collection tests.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestIntegerSetGenerator implements TestSetGenerator<Integer> {
  @Override

  // the CacheBuilder default).
  private Set<Integer> concurrencyLevels = Sets.newHashSet((Integer) null);
  private Set<Integer> initialCapacities = Sets.newHashSet((Integer) null);
  private Set<Integer> maximumSizes = Sets.newHashSet((Integer) null);
  private Set<DurationSpec> expireAfterWrites = Sets.newHashSet((DurationSpec) null);
  private Set<DurationSpec> expireAfterAccesses = Sets.newHashSet((DurationSpec) null);

      double setSize = rng.nextDouble();
      if (setSize < emptySetProportion) {
        sets[i] = ImmutableSet.of();
      } else if (setSize < emptySetProportion + singletonSetProportion) {
        sets[i] = ImmutableSet.of(PRESENT);
      } else {
        sets[i] = ImmutableSet.of(PRESENT, new Object());
      }

      if (rng.nextDouble() < hitRate) {
        queries[i] = PRESENT;
      } else {

        Helpers.mapEntry(k0(), v0()), Helpers.mapEntry(k1(), v0()), Helpers.mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = Sets.newHashSet();
    expected.add(Helpers.mapEntry(k0(), (Collection<V>) Sets.newHashSet(v0(), v3())));
    expected.add(Helpers.mapEntry(k1(), (Collection<V>) Sets.newHashSet(v0())));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap().entrySet()).testEquals();
  }

    testers.add(SetCreationTester.class);
    testers.add(SetHashCodeTester.class);
    testers.add(SetEqualsTester.class);
    testers.add(SetRemoveTester.class);
    // SetRemoveAllTester doesn't exist because, Sets not permitting
    // duplicate elements, there are no tests for Set.removeAll() that aren't
    // covered by CollectionRemoveAllTester.
    return testers;
  }

  @Override