@Test(expectedExceptions = NullPointerException.class)
 public void removeSong() {
   System.out.println("removeSong");
   when(albumDao.removeSong(backInBlackAlbum, shootToThrillSong)).thenReturn(backInBlackAlbum);
   AlbumDTO result = albumFacade.removeSong(backInBlackAlbum.getId(), shootToThrillSong.getId());
   assertEquals(mappingService.mapTo(backInBlackAlbum, AlbumDTO.class), result);
 }