@CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    collection.clear();
    assertTrue("After clear(), a collection should be empty.", collection.isEmpty());
    assertEquals(0, collection.size());
    assertFalse(collection.iterator().hasNext());
  }

  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = ZERO)

        UnsupportedOperationException.class,
        () -> collection.removeAll(MinimalCollection.of(e0())));
    expectUnchanged();
    assertTrue(collection.contains(e0()));
  }

  /*
   * AbstractCollection fails the removeAll(null) test when the subject
   * collection is empty, but we'd still like to test removeAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.

   *     to primitives
   * @throws NullPointerException if {@code collection} or any of its elements is null
   * @since 1.0 (parameter was {@code Collection<Short>} before 12.0)
   */
  public static short[] toArray(Collection<? extends Number> collection) {
    if (collection instanceof ShortArrayAsList) {
      return ((ShortArrayAsList) collection).toShortArray();
    }

import java.util.Collection;
import java.util.List;
import org.jspecify.annotations.NullMarked;

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

    return Multimaps.filterEntries(unfiltered, PREDICATE);
  }

  @Override
  protected Map<String, Collection<Integer>> makeEmptyMap() {
    Multimap<String, Integer> multimap = createMultimap();
    return multimap.asMap();
  }

  @Override
  protected Map<String, Collection<Integer>> makePopulatedMap() {
    Multimap<String, Integer> multimap = createMultimap();
    populate(multimap);

class PathTranslatingPostProcessor implements InterpolationPostProcessor {

    private final Collection<String> unprefixedPathKeys;
    private final File projectDir;
    private final PathTranslator pathTranslator;
    private final List<String> expressionPrefixes;

    PathTranslatingPostProcessor(
            List<String> expressionPrefixes,
            Collection<String> unprefixedPathKeys,
            File projectDir,

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class AbstractMultisetTester<E> extends AbstractCollectionTester<E> {
  protected final Multiset<E> getMultiset() {
    return (Multiset<E>) collection;
  }

  protected void initThreeCopies() {
    collection = getSubjectGenerator().create(e0(), e0(), e0());
  }

    assertTrue(copy instanceof ImmutableMultiset);
    return copy;
  }

  @CanIgnoreReturnValue
  @GwtIncompatible // SerializableTester
  static <E> Collection<E> reserializeAndAssertElementsEqual(Collection<E> original) {
    Collection<E> copy = reserialize(original);
    assertTrue(elementsEqual(original, copy));
    assertTrue(copy instanceof ImmutableCollection);
    return copy;
  }

import static java.util.Collections.emptyList;
import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multimap;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.junit.Ignore;

   *
   * @return set of column keys
   */
  Set<C> columnKeySet();

  /**
   * Returns a collection of all values, which may contain duplicates. Changes to the returned
   * collection will update the underlying table, and vice versa.
   *
   * @return collection of values
   */
  Collection<V> values();

  /**
   * Returns a view that associates each row key with the corresponding map from column keys to