@CollectionSize.Require(absent = ZERO)
  public void testPutDuplicateValuePreservesSize() {
    assertFalse(multimap().put(k0(), v0()));
    assertEquals(getNumElements(), multimap().size());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {
      resetContainer();
      K k = entry.getKey();

  @CollectionSize.Require(absent = ZERO)
  public void testPutDuplicateValuePreservesSize() {
    assertFalse(multimap().put(k0(), v0()));
    assertEquals(getNumElements(), multimap().size());
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutDuplicateValue() {
    List<Entry<K, V>> entries = copyToList(multimap().entries());

    for (Entry<K, V> entry : entries) {
      resetContainer();
      K k = entry.getKey();

 * implementation.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
public class MultimapTestSuiteBuilder<K, V, M extends Multimap<K, V>>
    extends PerCollectionSizeTestSuiteBuilder<
        MultimapTestSuiteBuilder<K, V, M>, TestMultimapGenerator<K, V, M>, M, Entry<K, V>> {

  public static <K, V, M extends Multimap<K, V>> MultimapTestSuiteBuilder<K, V, M> using(

  public void testTreeKeys() {
    ListMultimap<String, Integer> multimap = MultimapBuilder.treeKeys().arrayListValues().build();
    assertTrue(multimap.keySet() instanceof SortedSet);
    assertTrue(multimap.asMap() instanceof SortedMap);
  }

  public void testTreeKeys_gwtCompatible() {
    ListMultimap<String, Integer> multimap =

  @CollectionSize.Require(SEVERAL)
  public void testMultimapRemoveDeletesFirstOccurrence() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k0(), v1()), mapEntry(k0(), v0()));

    List<V> list = multimap().get(k0());
    multimap().remove(k0(), v0());
    assertContentsInOrder(list, v1(), v0());
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(SEVERAL)
  public void testRemoveAtIndexFromGetPropagates() {

    HashMultimap<K, V> multimap = HashMultimap.create();
    multimap.put(key, value);
    return multimap;
  }

  @Generates
  static <K, V> LinkedHashMultimap<K, V> generateLinkedHashMultimap(
      @Nullable K key, @Nullable V value) {
    LinkedHashMultimap<K, V> multimap = LinkedHashMultimap.create();
    multimap.put(key, value);
    return multimap;
  }

  @Generates

  public void testPutAllAddsAtEndInOrder() {
    List<V> values = asList(v3(), v1(), v4());

    for (K k : sampleKeys()) {
      resetContainer();

      List<V> expectedValues = copyToList(multimap().get(k));

      assertTrue(multimap().putAll(k, values));
      expectedValues.addAll(values);

      assertGet(k, expectedValues);
    }
  }

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

  }

  static <K extends @Nullable Object, V extends @Nullable Object> Multimap<K, V> multimap(
      Multimap<K, V> multimap, @Nullable Object mutex) {
    if (multimap instanceof SynchronizedMultimap || multimap instanceof BaseImmutableMultimap) {
      return multimap;
    }
    return new SynchronizedMultimap<>(multimap, mutex);
  }

import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A set multimap which forwards all its method calls to another set multimap. Subclasses should
 * override one or more methods to modify the behavior of the backing multimap as desired per the <a
 * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *