public void testPutAllIntoEmpty() {
    Multimap<K, V> target = getSubjectGenerator().create();
    assertEquals(!multimap().isEmpty(), target.putAll(multimap()));
    assertEquals(multimap(), target);
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAll() {
    Multimap<K, V> source =
        getSubjectGenerator().create(mapEntry(k0(), v3()), mapEntry(k3(), v3()));
    assertTrue(multimap().putAll(source));

  public void testPutAllIntoEmpty() {
    Multimap<K, V> target = getSubjectGenerator().create();
    assertEquals(!multimap().isEmpty(), target.putAll(multimap()));
    assertEquals(multimap(), target);
  }

  @MapFeature.Require(SUPPORTS_PUT)
  public void testPutAll() {
    Multimap<K, V> source =
        getSubjectGenerator().create(mapEntry(k0(), v3()), mapEntry(k3(), v3()));
    assertTrue(multimap().putAll(source));

    assertEquals(0, multimap().size());
    assertEmpty(multimap());
    assertEquals(multimap(), getSubjectGenerator().create());
    assertEmpty(multimap().entries());
    assertEmpty(multimap().asMap());
    assertEmpty(multimap().keySet());
    assertEmpty(multimap().keys());
    assertEmpty(multimap().values());
    for (K key : sampleKeys()) {
      assertGet(key);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)

    } catch (UnsupportedOperationException expected) {
    }
    assertMultimapRemainsUnmodified(multimap, originalEntries);

    // Test #putAll(Multimap<K, V>)
    Multimap<K, V> multimap2 = ArrayListMultimap.create();
    multimap2.put(sampleKey, sampleValue);
    try {
      multimap.putAll(multimap2);
      fail("putAll(Multimap<K, V>) succeeded on unmodifiable multimap");

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>.
 *

 * already in the multimap has no effect. This interface does not specify the ordering of the
 * multimap's keys. See the {@link Multimap} documentation for information common to all multimaps.
 *
 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
 * SortedSet} of values, while {@link Multimap#entries()} returns a {@link Set} of map entries.

     * present?
     */

    if (multimap.isEmpty()) {
      return of();
    }

    if (multimap instanceof ImmutableSetMultimap) {
      @SuppressWarnings("unchecked") // safe since multimap is not writable
      ImmutableSetMultimap<K, V> kvMultimap = (ImmutableSetMultimap<K, V>) multimap;
      if (!kvMultimap.isPartialView()) {
        return kvMultimap;
      }
    }

    for (Collection<V> valueCollection : multimap().asMap().values()) {
      SortedSet<V> valueSet = (SortedSet<V>) valueCollection;
      assertEquals(multimap().valueComparator(), valueSet.comparator());
    }
  }

  public void testAsMapGetImplementsSortedSet() {
    for (K key : multimap().keySet()) {
      SortedSet<V> valueSet = (SortedSet<V>) multimap().asMap().get(key);

    HashMultimap<String, Integer> multimap = HashMultimap.create();
    multimap.put("foo", 1);
    multimap.put("bar", 2);
    multimap.put("foo", 3);
    assertEquals(ImmutableSet.of(1, 3), multimap.get("foo"));
    assertEquals(2, multimap.expectedValuesPerKey);
  }

  public void testCreateFromMultimap() {
    HashMultimap<String, Integer> multimap = HashMultimap.create();
    multimap.put("foo", 1);
    multimap.put("bar", 2);

    HashMultimap<String, Integer> multimap = HashMultimap.create();
    multimap.put("foo", 1);
    multimap.put("bar", 2);
    multimap.put("foo", 3);
    assertEquals(ImmutableSet.of(1, 3), multimap.get("foo"));
    assertEquals(2, multimap.expectedValuesPerKey);
  }

  public void testCreateFromMultimap() {
    HashMultimap<String, Integer> multimap = HashMultimap.create();
    multimap.put("foo", 1);
    multimap.put("bar", 2);