public void deleteCommentById(final Long memberId, final Long commentId) {
        Comment comment = findComment(commentId);
        comment.validateWriterId(memberId);

        commentRepository.deleteById(commentId);
    }
@Test
    void 댓글을_삭제한다() {
        // given
        Comment saved = commentRepository.save(댓글_생성());

        // when & then
        assertDoesNotThrow(() -> commentService.deleteCommentById(1L, saved.getId()));
    }