* PeekingIterator#remove()} removes the same elements as the reference's iterator {@code
   * remove()}.
   */
  private static class PeekingIteratorTester<T extends @Nullable Object> extends IteratorTester<T> {
    private final Iterable<T> master;
    private @Nullable List<T> targetList;

    PeekingIteratorTester(Collection<T> master) {
      super(master.size() + 3, MODIFIABLE, master, IteratorTester.KnownOrder.KNOWN_ORDER);

import java.util.concurrent.ScheduledFuture;
import org.jspecify.annotations.Nullable;

/**
 * Helper interface to implement both {@link ListenableFuture} and {@link ScheduledFuture}.
 *
 * @author Anthony Zana
 * @since 15.0
 */
@GwtCompatible
public interface ListenableScheduledFuture<V extends @Nullable Object>

import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests that all {@code public static} methods "inherited" from superclasses are "overridden" in
 * each immutable-collection class. This ensures, for example, that a call written "{@code

import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests that all {@code public static} methods "inherited" from superclasses are "overridden" in
 * each immutable-collection class. This ensures, for example, that a call written "{@code

  /**
   * To avoid infinite recursion, test suites with these marker features won't have derived suites
   * created for them.
   */
  enum NoRecurse implements Feature<@Nullable Void> {
    SUBMAP,
    DESCENDING;

    @Override
    public Set<Feature<? super @Nullable Void>> getImpliedFeatures() {
      return emptySet();
    }
  }

  /**
   * Creates a suite whose map has some elements filtered out of view.
   *

// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public class SetMultimapAsMapTester<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMultimapTester<K, V, SetMultimap<K, V>> {
  public void testAsMapValuesImplementSet() {
    for (Collection<V> valueCollection : multimap().asMap().values()) {

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link GcFinalization}.
 *
 * @author Martin Buchholz
 * @author mike nonemacher
 */
@AndroidIncompatible // depends on details of gc

@NullUnmarked

import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicBoolean;
import org.jspecify.annotations.Nullable;

/**
 * Utilities necessary for working with libraries that supply plain {@link Future} instances. Note
 * that, whenever possible, it is strongly preferred to modify those libraries to return {@code

    final Alphabet alphabet;

    final @Nullable Character paddingChar;

    StandardBaseEncoding(String name, String alphabetChars, @Nullable Character paddingChar) {
      this(new Alphabet(name, alphabetChars.toCharArray()), paddingChar);
    }

    StandardBaseEncoding(Alphabet alphabet, @Nullable Character paddingChar) {
      this.alphabet = checkNotNull(alphabet);
      checkArgument(

    return delegate().edgeConnecting(endpoints);
  }

  @Override
  public @Nullable E edgeConnectingOrNull(N nodeU, N nodeV) {
    return delegate().edgeConnectingOrNull(nodeU, nodeV);
  }

  @Override
  public @Nullable E edgeConnectingOrNull(EndpointPair<N> endpoints) {
    return delegate().edgeConnectingOrNull(endpoints);
  }

  @Override