}

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
  public void testEquals_containingNull() {
    Collection<E> elements = getSampleElements(getNumElements() - 1);
    elements.add(null);

    collection = getSubjectGenerator().create(elements.toArray());
    assertTrue(
        "A Set should equal any other Set containing the same elements,"

        return false;
      }

      @Override
      public boolean removeAll(Collection<?> collection) {
        return removeAllKeys(unfiltered, predicate, collection);
      }

      @Override
      public boolean retainAll(Collection<?> collection) {
        return retainAllKeys(unfiltered, predicate, collection);
      }

      @Override
      public @Nullable Object[] toArray() {

        return false;
      }

      @Override
      public boolean removeAll(Collection<?> collection) {
        return removeAllKeys(unfiltered, predicate, collection);
      }

      @Override
      public boolean retainAll(Collection<?> collection) {
        return retainAllKeys(unfiltered, predicate, collection);
      }

      @Override
      public @Nullable Object[] toArray() {

            return parent.remove(o);
        }

        public boolean containsAll(final Collection<?> c) {
            return parent.containsAll(c);
        }

        public boolean addAll(final Collection<? extends E> c) {
            return parent.addAll(c);
        }

        public boolean addAll(final int index, final Collection<? extends E> c) {
            return parent.addAll(index, c);
        }

import com.google.common.collect.testing.SampleElements.Unhashables;
import java.util.Collection;
import java.util.List;

/**
 * Creates collections containing unhashable sample elements, to be tested.
 *
 * @author Regina O'Dell
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestUnhashableCollectionGenerator<T extends Collection<UnhashableObject>>
    implements TestCollectionGenerator<UnhashableObject> {

      resetContainer();
      Collection<V> collection = multimap().get(key);
      multimap().clear();
      assertEmpty(collection);
    }
  }

  @MapFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)
  public void testClearPropagatesToAsMapGet() {
    for (K key : sampleKeys()) {
      resetContainer();
      Collection<V> collection = multimap().asMap().get(key);

import com.google.common.collect.testing.features.CollectionSize;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.function.Predicate;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@link Collection#removeIf}. Can't be invoked directly; please
 * see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.

  }

  @Override
  public boolean containsAll(Collection<?> collection) {
    if (!allowNulls) {
      for (Object object : collection) {
        // behave badly
        if (object == null) {
          throw new NullPointerException();
        }
      }
    }
    return super.containsAll(collection);
  }

  @Override
  public Iterator<E> iterator() {

    putAll(multimap);
  }

  @Override
  Map<K, Collection<V>> createAsMap() {
    return createMaybeNavigableAsMap();
  }

  /**
   * {@inheritDoc}
   *
   * <p>Creates an empty {@code TreeSet} for a collection of values for one key.
   *
   * @return a new {@code TreeSet} containing a collection of values for one key
   */
  @Override
  SortedSet<V> createCollection() {

  /*
   * Previously we had a field named list that was initialized to the value of
   * collection in setUp(), but that caused problems when a tester changed the
   * value of list or collection but not both.
   */
  protected final List<E> getList() {
    return (List<E>) collection;
  }

  /**
   * {@inheritDoc}
   *
   * <p>The {@code AbstractListTester} implementation overrides {@link