public void testEntrySetEquals() {
    resetContainer(mapEntry(k0(), v0()), mapEntry(k1(), v0()), mapEntry(k0(), v3()));
    Set<Entry<K, Collection<V>>> expected = new HashSet<>();
    expected.add(mapEntry(k0(), (Collection<V>) newHashSet(v0(), v3())));
    expected.add(mapEntry(k1(), (Collection<V>) newHashSet(v0())));
    new EqualsTester().addEqualityGroup(expected, multimap().asMap().entrySet()).testEquals();
  }

  }

  public void testCopyOf_shortcut_empty() {
    Collection<String> c = ImmutableList.of();
    assertSame(c, ImmutableList.copyOf(c));
  }

  public void testCopyOf_shortcut_singleton() {
    Collection<String> c = ImmutableList.of("a");
    assertSame(c, ImmutableList.copyOf(c));
  }

  public void testCopyOf_shortcut_immutableList() {
    Collection<String> c = ImmutableList.of("a", "b", "c");

    }

    /**
     * Returns {@literal true} if the given {@link Collection} is {@literal null} or empty.
     *
     * @param collection the collection
     * @return {@literal true} if the collection is {@literal null} or empty
     */
    public static boolean isEmpty(final Collection<?> collection) {
        return collection == null || collection.isEmpty();
    }

    /**

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.codelibs.core.collection;

import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.util.Iterator;
import java.util.NoSuchElementException;

import org.codelibs.core.exception.ClUnsupportedOperationException;

      @SuppressWarnings("unchecked")
      @Override
      <K extends K0, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        // K must actually be K0, since enums are effectively final
        // (their subclasses are inaccessible)
        return (Map<K, Collection<V>>) new EnumMap<K0, Collection<V>>(keyClass);
      }
    };
  }

  private static final class ArrayListSupplier<V extends @Nullable Object>

      @SuppressWarnings("unchecked")
      @Override
      <K extends K0, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        // K must actually be K0, since enums are effectively final
        // (their subclasses are inaccessible)
        return (Map<K, Collection<V>>) new EnumMap<K0, Collection<V>>(keyClass);
      }
    };
  }

  private static final class ArrayListSupplier<V extends @Nullable Object>

    @Override
    public Entry<K, Collection<V>>[] createArray(int length) {
      return (Entry<K, Collection<V>>[]) new Entry<?, ?>[length];
    }

    @Override
    public Iterable<Entry<K, Collection<V>>> order(List<Entry<K, Collection<V>>> insertionOrder) {
      Map<K, Collection<V>> map = new HashMap<>();
      List<Entry<K, V>> builder = new ArrayList<>();
      for (Entry<K, Collection<V>> entry : insertionOrder) {

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.CompatibleWith;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A collection that supports order-independent equality, like {@link Set}, but may have duplicate

      resetContainer();

      int size = getNumElements();

      Collection<V> collection = multimap().asMap().get(key);
      assertNotNull(collection);
      Collection<V> expectedCollection = copyToList(collection);

      multimap().put(key, v3());
      expectedCollection.add(v3());
      assertEqualIgnoringOrder(expectedCollection, collection);
      assertEquals(size + 1, multimap().size());
    }
  }

      resetContainer();

      int size = getNumElements();

      Collection<V> collection = multimap().asMap().get(key);
      assertNotNull(collection);
      Collection<V> expectedCollection = copyToList(collection);

      multimap().put(key, v3());
      expectedCollection.add(v3());
      assertEqualIgnoringOrder(expectedCollection, collection);
      assertEquals(size + 1, multimap().size());
    }
  }