### Question:
CommentService { public CommentDto findCommentByPrimaryKey(String commentId) { return commentDao.findById(commentId).map(commentMapper::toDto).orElseThrow(ResourceNotFoundException::new); } CommentService(CommentDao commentDao, CommentMapper commentMapper); Page<CommentDto> findCommentByCondition(CommentDto commentDto, Pageable pageable); CommentDto findCommentByPrimaryKey(String commentId); void saveOrUpdate(CommentDto commentDto); void deleteCommentByIds(List<String> commentIds);  }### Answer:
@Test void testFindCommentByPrimaryKey() { CommentDto result = commentService.findCommentByPrimaryKey("commentId"); Assertions.assertEquals(new CommentDto(), result); }