您应该如何将服务层方法划分为可测试的块？

Question

exports.sendFeedbackServiceProviderMethod = function(req, res, next) {

    var articleId = req.body.articleId
    var commentId = req.body.commentId
    var action = req.body.action
    var meta = req.body.meta

    var Target
    var targetId
    if (articleId) {
        Target = Article
        targetId = articleId
    }
    else if (commentId) {
        Target = Comment
        targetId = commentId
    }

    //1. find the target
    //Note: will refetch when need to send json, since feedback has been changed
    Target.findById(targetId).exec(function(err, target) {
        if (err)
            return next(err)
        if (!target)
            return next(helper.getGeneralError('target does not exist'))


        //2. find the feedback
        var criteria = {}
        criteria['statusMeta.createdBy'] = req.user
        if (action === 'like' || action === 'dislike' || action === 'unlike' || action === 'undislike')
            criteria['type'] = {$in: ['like', 'dislike']}
        else if (action === 'share' || action === 'unshare')
            criteria['type'] = 'share'
        if (articleId)
            criteria['target.article'] = articleId
        else if (commentId)
            criteria['target.comment'] = commentId

        Feedback.find(criteria).exec(function(err, feedbacks) {

            if (err)
                next(err)
            if (feedbacks.length === 0) {
                //3. Feedback does not exist, create it
                var newFeedback = new Feedback()

                if (action === 'like' || action === 'dislike' || action === 'share') {
                    newFeedback.type = action
                    newFeedback.status = 'normal'
                    newFeedback.statusMeta.createdBy = req.user
                    if (articleId)
                        newFeedback.target.article = targetId
                    else if (commentId)
                        newFeedback.target.comment = targetId
                    if (meta)
                        newFeedback.meta= meta
                }

                newFeedback.save(function(err) {
                    if (err)
                        return next(err)

                    //4. save to target feedbacks list
                    target.feedbacks.push(newFeedback)
                    target.save(function(err) {
                        if (err)
                            return next(err)

                        //5. save to user feedbacks list
                        req.user.feedbacks.push(newFeedback)
                        req.user.save(function(err) {
                            if (err)
                                return next(err)

                            //6. done
                            //Note: send the target!
                            //Note: refetch target and populate, since its feedbacks have been changed
                            var query = Target.findById(targetId)
                            populateUsersForQuery(query)
                            populateFeedbacksForQuery(query)
                            query.exec(function(err, target) {
                                if (err)
                                    return next(err)
                                return res.json(target)
                            })
                        })
                    })
                })
            }
            else {
                //3x. Found the feedback, update it
                var feedback = feedbacks[0] //must be length 1

                if (action === 'like' || action === 'dislike' || action === 'share') {
                    feedback.type = action
                    feedback.status = 'normal'
                    feedback.statusMeta.updatedBy = req.user
                    feedback.statusMeta.updatedDate = new Date
                }
                else if (action === 'unlike' || action === 'undislike' || action === 'unshare') {
                    feedback.status = 'deleted'
                    feedback.statusMeta.deletedBy = req.user
                    feedback.statusMeta.deletedDate = new Date
                }
                if (meta)
                    feedback.meta= meta

                feedback.save(function(err) {
                    if (err)
                        return next(err)

                    //4x. done
                    //Note: send the target!
                    //Note: refetch target and populate, since its feedbacks have been changed
                    var query = Target.findById(targetId)
                    populateUsersForQuery(query)
                    populateFeedbacksForQuery(query)
                    query.exec(function(err, target) {
                        if (err)
                            return next(err)
                        return res.json(target)
                    })
                })
            }
        })
    })
}

我有这段代码，它很大，我想知道如何去测试它。我应该把它分成更小的部分，我应该如何做到这一点，或者我应该保持原样并测试整个块。另外，我不确定测试服务层方法的标准方法是什么，我们是否只是像这里一样测试整个路由：

describe('POST /user', function() {
  it('user.name should be an case-insensitive match for "john"', function(done) {
    request(app)
      .post('/user')
      .send('name=john') // x-www-form-urlencoded upload
      .set('Accept', 'application/json')
      .expect(function(res) {
        res.body.id = 'some fixed id';
        res.body.name = res.body.name.toLowerCase();
      })
      .expect(200, {
        id: 'some fixed id',
        name: 'john'
      }, done);
  });
});

或者我应该检查每个被修改对象的状态？你能告诉我如何为上面的方法设置单元测试以及我应该如何划分它以使测试更容易？

Answer 1

您的方法 sendFeedbackServiceProviderMethod 有太多违反 SRP (Single Responsibility Principle) 的责任。您绝对应该考虑使用例如Split phase technique 进行重构。完成后，您可以独立测试这些功能。所有这些find、findById、update 和save 功能表示不同的操作，因此可能表示不同的功能。当然，您可以将当前测试保留为验收测试，并在重构这个庞大的功能后创建适当的单元测试。

您的函数也有很多违反 SLA (Single Level of Abstraction) 的抽象级别。高级概念与低级细节混合在一起，表明要进行重构。

我建议你将你的 cmets 转换为自解释函数并对它们进行单元测试。