如何使用笑话功能发送响应？ 它给出了异步回调错误

Question

I try to mock model response using jest. It will go in my jest.mock.createMondayBox function and it can print "hello world", which means it can really go inside mock model that replaces the original model.

models/mondayModel.js

var mondayModel = function() {
  function createBox (req, payload, callback) { 
   ...
   boxClient.request(req, {
     method: 'POST'
     path:
     body: 
     headers: { }
   }, function(error, response) {
      if(error || (response.statusCode && response.statusCode !== 200)) { 
        return callback(new ErrorObject({
           errorName:'createBoxFailure', 
           errorMessage: 'Error in creating box'
        })
      }
      return callback(null, {resultSet: response.body})
   })

  }
  function fnB (req, callback) { }
  function fnC (req, callback) { }
  function fnD (req, callback) { }
  return {
    createBox: createBox,
    fnB: fnB,
    fnC: fnC,
    fnD: fnD
  }
}

module.exports = mondayModel

controller/boxController.js

var MondayModel = require('../models/mondayModel');


function createMondayBox(req, res, next) {
   ...
   var mondayModel = new MondayModel();
   mondayModel.createBox(req, payload, function(error, result) {

      if(error) {
         res.json({'status': 'BADREQUEST', 'statusCode': 400})

      } else {
         var mondaybox = result.resultSet.mondayboxes && result.resultSet.mondayboxes[0]

         var mappedResponse = Response.mapCreateMondaybox(req, resultSet);
         utils.logKK(req, utils.getKK(mappedResponse.mondayboxes[0]))
         res.json(mappedResponse);
      }

   ...
   }
}

boxController-test.jest

let boxController = null

describe('money tracker', () => {
    beforeAll(() => {        
        jest.mock('../../../../models/mondayBox',
            () => function mondayBoxModel() {
               console.log("hello world")
               return {
                createBox: (req, payload, callback) => {
                  return callback(null, {
                        resultSet: {
                            mondayboxes: [{ name: '1' }, { name: '2' }]
                        },
                        json: jest.fn()
                    })}
                fnB: jest.fn(),
                fnC: jest.fn(),
                fnD: jest.fn()
                }
               }
        }))    
    )
        boxController = require('../controllers/boxController')
    })

    test('success case', done => {
       const req = {}
       const res = new Promise(r =>
         r({ json: jest.fn(), status: jest.fn() })
       )
       mondayBoxController.createMondayBox(req, res, (cbErr, cbRes) => {
          expect(res.json).toBeCalled();
          done()
       }) 
    }
}

TypeError: res.json is not a function

May I know how to solve this problem? How to write mock model response? Thanks

Answer 1

First of all you need to test the controller only, hence you should do

Update the controller to

var MondayModel = require('../models/mondayModel');


function createMondayBox(req, res, next) {
 ...
 var mondayModel = new MondayModel();
 mondayModel.createBox(req, payload, function(error, result) {

   if(error) {
     res.json({'status': 'BADREQUEST', 'statusCode': 400})

   } else {
     var mondaybox = result.resultSet.mondayboxes && 
     result.resultSet.mondayboxes[0]

     var mappedResponse = Response.mapCreateMondaybox(req, resultSet);
     utils.logKK(req, utils.getKK(mappedResponse.mondayboxes[0]))
     res.json(mappedResponse);
     next();
   }

  ...
 }
}

And in test file:

import {createRequest, createResponse}  from 'node-mocks-http'
import boxController from 'controller/boxController.js'
import mondayBoxModal from 'models/mondayBox';

jest.mock('models/mondayBox', () => () => ({ createBox: (req, payload, cb) => cb(null, { resultSet: { mondayboxes: ['resultsData']} } }));

describe('money tracker', () => {
 let req;
 let res;
 let next = jest.fn;
 beforeEach(() => {
    jest.clearAllMocks();
    req  = createRequest({
      method: 'GET',
      url: '/user/42',
      params: {
       id: 42
      }
    });

    res = httpMocks.createResponse();
    res.json = jest.fn;

 })

 test('success case', done => {
   const req = {}

   mondayBoxController.createMondayBox(req, res, (cbErr, cbRes) => {
      expect(res.json).toBeCalled();
      done()
   })
}

}

Answer 2

Your function transfer(req, res, next) takes 3 argument and would use res.json() while your call boxController.transfer(req, {}, fn) is passing an empty object. It probably fails silently here.

And transfer didn't call next at all in your sample.

Please make sure your example resembles the actual code accurately.

Update

It has nothing to do with async or not

if you write this

const res = new Promise(r =>
  r({ json: jest.fn(), status: jest.fn() })
)
mondayBoxController.createMondayBox(req, res, (cbErr, cbRes) => {
  expect(res.json).toBeCalled();
  done();
})

then

mondayModel.createBox(req, payload, function (error, result) {
  console.log(res); // Promise, which has no json method
  console.log(res.json); // undefined
  // but
  console.log(await res); // the desired mocked res obj
  // btw this is incorrect usage of await
  if (error) {
    res.json();
  } else {
    ...
  }
});

res in mondayModel.createBox 's callback is exactly what you passed into mondayBoxController.createMondayBox(req, res, handler) .

instead, do this

const res = {
  json: jest.fn(); // or whatever behaviour you desire
};
mondayBoxController.createMondayBox(req, res, handler);