return new TrackedRunnable() {
      private volatile boolean done = false;

      @Override
      public boolean isDone() {
        return done;
      }

      @Override
      public void run() {
        try {
          delay(timeoutMillis);
          done = true;
        } catch (InterruptedException ok) {
        }
      }
    };
  }

    @Override
    public BigInteger next(BigInteger value) {
      return value.add(BigInteger.ONE);
    }

    @Override
    public BigInteger previous(BigInteger value) {
      return value.subtract(BigInteger.ONE);
    }

    @Override
    BigInteger offset(BigInteger origin, long distance) {
      checkNonnegative(distance, "distance");

   *
   * <p>Duplicate elements are considered equal. For example, the list [1, 1] will have only one
   * permutation, instead of two. This is why the elements have to implement {@link Comparable}.
   *
   * <p>An empty iterable has only one permutation, which is an empty list.
   *
   * <p>This method is equivalent to {@code Collections2.orderedPermutations(list,
   * Ordering.natural())}.

      for (; ; ) {
        boolean done = true;
        for (int i = 0; i < aa.length(); i++) {
          double v = aa.get(i);
          assertTrue(v >= 0);
          if (v != 0) {
            done = false;
            if (aa.compareAndSet(i, v, v - 1.0)) {
              ++counts;
            }
          }
        }
        if (done) {
          break;
        }
      }
    }

      for (; ; ) {
        boolean done = true;
        for (int i = 0; i < aa.length(); i++) {
          double v = aa.get(i);
          assertTrue(v >= 0);
          if (v != 0) {
            done = false;
            if (aa.compareAndSet(i, v, v - 1.0)) {
              ++counts;
            }
          }
        }
        if (done) {
          break;
        }
      }
    }

 * Executor, and sequentially such that no two will ever be running at the same time.
 *
 * <p>Tasks submitted to {@link #execute(Runnable)} are executed in FIFO order.
 *
 * <p>The execution of tasks is done by one thread as long as there are tasks left in the queue.
 * When a task is {@linkplain Thread#interrupt interrupted}, execution of subsequent tasks
 * continues. See {@link QueueWorker#workOnQueue} for details.
 *

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public class ListsImplTest extends TestCase {

  /** Describes how a list is modifiable */
  public enum Modifiability {
    NONE, // immutable lists
    BY_ELEMENT, // elements can change (set), but not structure
    DIRECT_ONLY, // Element can be added and removed only via direct calls, not through iterators

  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Boolean> none = Arrays.<Boolean>asList();
    assertThat(Booleans.toArray(none)).isEqualTo(EMPTY);

    List<Boolean> one = Arrays.asList(false);
    assertThat(Booleans.toArray(one)).isEqualTo(ARRAY_FALSE);

    boolean[] array = {false, false, true};

    List<Boolean> three = Arrays.asList(false, false, true);

  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Boolean> none = Arrays.<Boolean>asList();
    assertThat(Booleans.toArray(none)).isEqualTo(EMPTY);

    List<Boolean> one = Arrays.asList(false);
    assertThat(Booleans.toArray(one)).isEqualTo(ARRAY_FALSE);

    boolean[] array = {false, false, true};

    List<Boolean> three = Arrays.asList(false, false, true);

 *
 * <p>In order to allow proper garbage collection of unused locks, the edges of the lock graph are
 * weak references.
 *
 * <p><strong>Performance</strong>
 *
 * <p>The extra bookkeeping done by cycle detecting locks comes at some cost to performance.
 * Benchmarks (as of December 2011) show that:
 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as