return parent.isEmpty();
    }

    /**
     * Returns true if this map contains a mapping for the specified key.
     *
     * @param key the key whose presence in this map is to be tested
     * @return true if this map contains a mapping for the specified key
     */
    @Override
    public boolean containsKey(final Object key) {
        return parent.containsKey(key);
    }

    /**

 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;

/**
 * Creates iterators to be tested.
 *
 * @param <E> the element type of the iterator.
 * @author George van den Driessche
 */
@GwtCompatible
public interface TestIteratorGenerator<E> {
  Iterator<E> get();

     *
     * @param testName name of the test case
     */
    public AppTest( String testName )
    {
        super( testName );
    }

    /**
     * @return the suite of tests being tested
     */
    public static Test suite()
    {
        return new TestSuite( AppTest.class );
    }

    /**
     * Rigorous Test :-)
     */
    public void testApp()
    {

@GwtIncompatible
@NullUnmarked
public class PackageSanityTests extends AbstractPackageSanityTests {
  public PackageSanityTests() {
    // package private classes like FunctionalEquivalence are tested through the public API.
    publicApiOnly();
  }

import com.google.common.annotations.GwtCompatible;
import java.util.List;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates sets, containing sample elements, to be tested.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@NullMarked
public interface TestListGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  List<E> create(Object... elements);

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates queues, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public interface TestQueueGenerator<E extends @Nullable Object> extends TestCollectionGenerator<E> {
  @Override
  Queue<E> create(Object... elements);

   - If you edit, you’re a collaborator, not a reviewer, and cannot merge.

6. **Testing**:
   - Assume the submitter tested the code. If testing is unclear, ask for details (e.g., “How was this tested?”).
   - Reject untested PRs unless testing is infeasible, then assist with test setup.

## Tips for Success

import com.google.common.collect.testing.TestCollectionGenerator;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates multisets, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public interface TestMultisetGenerator<E extends @Nullable Object>
    extends TestCollectionGenerator<E> {
  @Override

import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates maps, containing sample elements, to be tested.
 *
 * @author George van den Driessche
 */
@GwtCompatible
@NullMarked
public interface TestMapGenerator<K extends @Nullable Object, V extends @Nullable Object>

import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates bimaps, containing sample entries, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestBiMapGenerator<K extends @Nullable Object, V extends @Nullable Object>
    extends TestContainerGenerator<BiMap<K, V>, Entry<K, V>> {