*/
  @J2ktIncompatible // serialization
  static class SerializedForm<K, V> implements Serializable {
    // This object retains references to collections returned by keySet() and value(). This saves
    // bytes when the both the map and its keySet or value collection are written to the same
    // instance of ObjectOutputStream.

    AssertionFailedError failure = new AssertionFailedError(message);
    failure.initCause(cause);
    return failure;
  }

  // This test covers a bug where an Error thrown from a callback could cause the TimeoutFuture to
  // never complete when timing out.  Notably, nothing would get logged since the Error would get

  static <E> Queue<E> discardingQueue() {
    return (Queue) DISCARDING_QUEUE;
  }

  /*
   * Note: All of this duplicate code sucks, but it saves a lot of memory. If only Java had mixins!
   * To maintain this code, make a change for the strong reference type. Then, cut and paste, and

  static {
    ImmutableSet.Builder<Integer> intValues = ImmutableSet.builder();
    // Add boundary values manually to avoid over/under flow (this covers 2^N for 0 and 31).
    intValues.add(Integer.MAX_VALUE - 1, Integer.MAX_VALUE);
    // Add values up to 40. This covers cases like "square of a prime" and such.
    for (int i = 1; i <= 40; i++) {
      intValues.add(i);
    }

    manager.stopAsync();
    assertThrows(TimeoutException.class, () -> manager.awaitStopped(1, TimeUnit.MILLISECONDS));
    manager.awaitStopped(5, SECONDS); // no exception thrown
  }

  /**
   * This covers a case where if the last service to stop failed then the stopped callback would
   * never be called.
   */
  public void testSingleFailedServiceCallsStopped() {
    Service a = new FailStartService();

    }
  }

  private static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

  // This one-liner saves us from some ugly casts
  protected Entry<K, V> entry(K key, V value) {
    return Helpers.mapEntry(key, value);
  }

  @Override
  protected void expectContents(Collection<Entry<K, V>> expected) {

   * This is because the {@code forTree()}-based implementations don't keep track of visited nodes,
   * and therefore don't need to call `equals()` or `hashCode()` on the node objects; this saves
   * both time and space versus traversing the same graph using {@code forGraph()}.
   *
   * <p>Providing a graph to be traversed for which there is more than one path from the start
   * node(s) to any node may lead to:

        .addEqualityGroup(Collections.reverseOrder())
        .testEquals();
  }

  public void testReverseOfReverseSameAsForward() {
    // Not guaranteed by spec, but it works, and saves us from testing
    // exhaustively
    assertSame(numberOrdering, numberOrdering.reverse().reverse());
  }

  private enum StringLengthFunction implements Function<String, Integer> {
    StringLength;

        .addEqualityGroup(Collections.reverseOrder())
        .testEquals();
  }

  public void testReverseOfReverseSameAsForward() {
    // Not guaranteed by spec, but it works, and saves us from testing
    // exhaustively
    assertSame(numberOrdering, numberOrdering.reverse().reverse());
  }

  private enum StringLengthFunction implements Function<String, Integer> {
    StringLength;

    AssertionFailedError failure = new AssertionFailedError(message);
    failure.initCause(cause);
    return failure;
  }

  // This test covers a bug where an Error thrown from a callback could cause the TimeoutFuture to
  // never complete when timing out.  Notably, nothing would get logged since the Error would get