@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); }