SettableFuture<String> nested = SettableFuture.create();
    assertTrue(future.setFuture(nested));
    // Later attempts to set the future should return false.
    assertFalse(future.set("x"));
    assertFalse(future.setException(new Exception("bar")));
    assertFalse(future.setFuture(SettableFuture.<String>create()));
    // Check that the future has been set properly.
    assertFalse(future.isDone());

  @Override
  public boolean setException(Throwable throwable) {
    return super.setException(throwable);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setFuture(ListenableFuture<? extends V> future) {
    return super.setFuture(future);
  }

  private SettableFuture() {}

  @Override
  public boolean setException(Throwable throwable) {
    return super.setException(throwable);
  }

  @CanIgnoreReturnValue
  @Override
  public boolean setFuture(ListenableFuture<? extends V> future) {
    return super.setFuture(future);
  }

  private SettableFuture() {}

  }

  @Override
  public void run() {
    InterruptibleTask<?> localTask = task;
    if (localTask != null) {
      localTask.run();
    }
    /*
     * In the Async case, we may have called setFuture(pendingFuture), in which case afterDone()
     * won't have been called yet.
     */
    this.task = null;
  }

  @Override
  protected void afterDone() {
    super.afterDone();

import com.google.common.util.concurrent.AbstractFuture.TrustedFuture;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link AbstractFuture} that use a {@link TrustedFuture} for {@link
 * AbstractFuture#setFuture} calls.
 */
@GwtCompatible
@NullUnmarked
public class TrustedInputFutureTest extends AbstractAbstractFutureTest {
  @Override
  AbstractFuture<Integer> newDelegate() {

import com.google.common.util.concurrent.AbstractFuture.TrustedFuture;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link AbstractFuture} that use a non-{@link TrustedFuture} for {@link
 * AbstractFuture#setFuture} calls.
 */
@GwtCompatible
@NullUnmarked
public class UntrustedInputFutureTest extends AbstractAbstractFutureTest {
  @Override
  AbstractFuture<Integer> newDelegate() {

            executor.execute(runnable);
          }
        };
    Future<?> future = newFutureInstance();
    future
        .getClass()
        .getMethod(
            "setFuture",
            future.getClass().getClassLoader().loadClass(ListenableFuture.class.getName()))
        .invoke(future, badFuture);
    CancellationException expected = assertThrows(CancellationException.class, () -> future.get());

            executor.execute(runnable);
          }
        };
    Future<?> future = newFutureInstance();
    future
        .getClass()
        .getMethod(
            "setFuture",
            future.getClass().getClassLoader().loadClass(ListenableFuture.class.getName()))
        .invoke(future, badFuture);
    CancellationException expected = assertThrows(CancellationException.class, () -> future.get());

       * even with the above null checks.)
       */
      timeoutFutureRef = null;
      if (delegate.isDone()) {
        timeoutFuture.setFuture(delegate);
      } else {
        try {
          @RetainedLocalRef ScheduledFuture<?> timer = timeoutFuture.timer;
          timeoutFuture.timer = null; // Don't include already elapsed delay in delegate.toString()