public List<PhotoAlbum> split(int numberOfNewAlbums) {
    return IntStream.range(1, numberOfNewAlbums + 1)
        .mapToObj(
            i ->
                new PhotoAlbum(
                    String.format("%s-pt%d", id, i),
                    String.format("%s (%d/%d)", id, i, numberOfNewAlbums),
                    description))
        .collect(Collectors.toList());
  }
@Test
  public void splitNegative() {
    PhotoAlbum originalAlbum = new PhotoAlbum("123", "MyAlbum", DESCRIPTION);
    List<PhotoAlbum> actual = originalAlbum.split(-1);
    Truth.assertThat(actual).isEmpty();
  }