return "zero";
  }

  @Override
  protected Collection<Integer> getValueNotInPopulatedMap() throws UnsupportedOperationException {
    return Lists.newArrayList(0);
  }

  /**
   * The version of this test supplied by {@link MapInterfaceTest} fails for this particular Map
   * implementation, because {@code map.get()} returns a view collection that changes in the course

import java.util.Collection;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.Nullable;

/**
 * A {@link BlockingQueue} which forwards all its method calls to another {@link BlockingQueue}.
 * Subclasses should override one or more methods to modify the behavior of the backing collection

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.features.CollectionSize;
import java.util.Collection;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * The subject-generator interface accepted by Collection testers, for testing a Collection at one
 * particular {@link CollectionSize}.
 *
 * <p>This interface should not be implemented outside this package; {@link

    /**
     * Test method for
     * {@link org.codelibs.core.collection.EmptyIterator#EmptyIterator()}.
     */
    @Test
    public void testEmptyIterator() {
        final EmptyIterator<String> emptyIterator = new EmptyIterator<String>();
        assertThat(emptyIterator, is(notNullValue()));
    }

    /**
     * Test method for {@link org.codelibs.core.collection.EmptyIterator#remove()}
     * .
     */
    @Test

   * half of that is more awkward to arrange...
   */
  private static <T> Iterable<T> iterable(Collection<T> collection) {
    // return collection::iterator;
    return new Iterable<T>() {
      @Override
      public Iterator<T> iterator() {
        return collection.iterator();
      }
    };
  }

  public void testEquals() {
    new EqualsTester()

 * but reduces variability and avoids starvation.
 *
 * <p>This class and its iterator implement all of the optional methods of the {@link
 * Collection} and {@link Iterator} interfaces.
 *
 * @author Doug Lea
 * @author Justin T. Sampson
 * @param <E> the type of elements held in this collection
 */
// TODO(kak): consider removing some of the @CanIgnoreReturnValue annotations as appropriate
@NullUnmarked

import static java.util.Collections.singletonList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Iterators;
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.Collections;

import com.google.common.collect.testing.features.CollectionSize;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Generator for collection of a particular size.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.misc;

import static org.codelibs.core.collection.ArrayUtil.asArray;

import java.util.Collection;
import java.util.Map;

import org.codelibs.core.collection.ArrayUtil;
import org.codelibs.core.exception.ClIllegalArgumentException;
import org.codelibs.core.exception.ClIllegalStateException;

import static com.google.common.collect.testing.features.FeatureUtil.addImpliedFeatures;
import static java.util.Arrays.asList;
import static java.util.Collections.disjoint;
import static java.util.Collections.unmodifiableSet;
import static java.util.logging.Level.FINER;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.features.ConflictingRequirementsException;