node.js - Stub not working when writing unit test in Node using Express

Question

Alright, so I have a very simple API that basically returns information on currencies. I am trying to use the clean code approach and I am having a hard time making this test work. Here is what I got so far (I used ** wrapping the main statements):

This is controllers/getCurrency.js

const makeGetCurrency = ({ errorMessages, retrieveCurrency }) => {
    return async function getCurrency(httpRequest, myCache) {
        try {
            const {
                from,
                to,
                amount
            } = httpRequest.query

            const { ip, headers, source = {} } = httpRequest
            source.ip = ip
            source.browser = headers["User-Agent"]
            if (headers["Referer"]) {
                source.referer = headers["Referer"]
            }

            **const currencyConversion = await retrieveCurrency({ from, to, amount, myCache })**
            return {
                statusCode: 200,
                body: currencyConversion
            }

        }
        catch (err) {
            const { status, body } = errorMessages[err.message] || { status: 400, body: err.message }
            return {
                headers: {
                    "Content-Type": "application/json",
                },
                statusCode: status,
                body: {
                    error: body,
                }
            }
        }
    }
}

That is the controller I am trying to test. What I need to mock is this return:

• const currencyConversion = await retrieveCurrency

This function is being passed by another parent file called: controllers/index.js

const makeGetHealth = require('./health')
const makeGetCurrency = require('./currency/getCurrency')
const errorMessages = require('../error-messages.json')


//use-cases
**const { retrieveCurrency } = require('../_use-cases')**

const getHealth = makeGetHealth()
const getCurrency = makeGetCurrency({ errorMessages, retrieveCurrency })

module.exports = {
  getHealth,
  getCurrency,
}

Since retrieveCurrency is actually exported on use-cases/index.js I am trying to test the API like below:

const useCases = require('../../src/_use-cases')

describe("GET /currency ", () => {
    let sandbox

    beforeEach(() => {
        sandbox = sinon.createSandbox()
    })

    //test a function for a specific case
    it("returns status 200 ", async () => {
        **const retrieveCurrencyStub = sandbox.stub(useCases, 'retrieveCurrency').resolves({
            test: 'test'
        })**
        const { statusCode, body } = await chai.request(createServer()).get('/conversion?from=USD&to=BRL&amount=10')
        console.log(body) //not returning my stub's response
        expect(statusCode).to.equal(200)
        expect(retrieveCurrencyStub).to.be.called //is never called
    })

That is how my routes are setup

const setUpRoutes = (myCache) => {

  app.get('/health', expressCallBack(getHealth, myCache))
  app.get('/conversion', expressCallBack(getConversion, myCache))
  app.post('/currency', expressCallBack(postCurrency, myCache))
  app.delete('/currency', expressCallBack(deleteCurrency, myCache))

  return app
}

Does anyone know how to make this work?

Thank you so much

Answer 1

等待大神答复