@Override
    protected List<E> delegate() {
      return delegate;
    }

    @Override
    public int size() {
      return delegate.size() + delta;
    }
  }

  @SuppressWarnings("JoinIterableIterator") // explicitly testing iterator overload, too
  public void testNoSpecialNullBehavior() {
    checkNoOutput(J, iterable);
    checkResult(J, iterable1, "1");
    checkResult(J, iterable12, "1-2");