new TestStringSetGenerator() {
                  @Override
                  protected Set<String> create(String[] elements) {
                    return Sets.union(Sets.<String>newHashSet(), Sets.<String>newHashSet());
                  }
                })
            .named("empty U empty")
            .withFeatures(
                CollectionSize.ZERO, CollectionFeature.NONE, CollectionFeature.ALLOWS_NULL_VALUES)

    Set<Feature<?>> features = newHashSet(FOO);
    assertThat(addImpliedFeatures(features)).isSameInstanceAs(features);
  }

  public void testAddImpliedFeatures_addsImpliedFeatures() {
    assertThat(addImpliedFeatures(newHashSet(FOO))).containsExactly(FOO);

    assertThat(addImpliedFeatures(newHashSet(IMPLIES_IMPLIES_FOO)))
        .containsExactly(IMPLIES_IMPLIES_FOO, IMPLIES_FOO, FOO);

                new TestStringSetGenerator() {
                  @Override
                  protected Set<String> create(String[] elements) {
                    return Sets.union(Sets.<String>newHashSet(), Sets.<String>newHashSet());
                  }
                })
            .named("empty U empty")
            .withFeatures(
                CollectionSize.ZERO, CollectionFeature.NONE, CollectionFeature.ALLOWS_NULL_VALUES)

    expected.put(k0(), newHashSet(v0(), v3()));
    expected.put(k1(), newHashSet(v0()));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap()).testEquals();
  }

  @CollectionSize.Require(SEVERAL)
  public void testEntrySetEquals() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k1(), v0()), mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = newHashSet();

import static com.google.common.collect.Sets.newHashSet;

import com.google.common.base.Predicate;
import com.google.common.collect.FilteredCollectionsTestUtil.AbstractFilteredSetTest;
import java.util.Set;

public final class SetsFilterHashSetTest extends AbstractFilteredSetTest<Set<Integer>> {
  @Override
  Set<Integer> createUnfiltered(Iterable<Integer> contents) {
    return newHashSet(contents);
  }

  @Override

package com.google.common.collect.testing.google;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.Sets.newTreeSet;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST_2;

                            ? newHashSet(asList(elements).subList(0, size - 1))
                            : newHashSet(elements);
                    // Remove first element, if size > 0
                    Set<String> set2 =
                        (size > 0)
                            ? newHashSet(asList(elements).subList(1, size))
                            : Sets.<String>newHashSet();

    expected.put(k0(), newHashSet(v0(), v3()));
    expected.put(k1(), newHashSet(v0()));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap()).testEquals();
  }

  @CollectionSize.Require(SEVERAL)
  public void testEntrySetEquals() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k1(), v0()), mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = newHashSet();

    assertEquals("[" + JOINER.join(map.keySet()) + "]", map.keySet().toString());
    assertEquals("[" + JOINER.join(map.values()) + "]", map.values().toString());

    assertEquals(newHashSet(map.entrySet()), map.entrySet());
    assertEquals(newHashSet(map.keySet()), map.keySet());
  }

    assertEquals("[" + joiner.join(map.keySet()) + "]", map.keySet().toString());
    assertEquals("[" + joiner.join(map.values()) + "]", map.values().toString());

    assertEquals(newHashSet(map.entrySet()), map.entrySet());
    assertEquals(newHashSet(map.keySet()), map.keySet());
  }