javascript - expressJS/jestJS : How to split get() function to write simple jest unit test?

如何在expressJS应用程序中定义get()路由，以进行简单的单元测试？

因此，第一步，我将get()的功能移到了自己的文件中:

index.js

const express = require('express')
const socketIo = require('socket.io')
const Gpio = require('pigpio').Gpio

const app = express()
const server = http.createServer(app)
const io = socketIo(server)

const setStatus = require('./lib/setStatus.js')

app.locals['target1'] = new Gpio(1, { mode: Gpio.OUTPUT })

app.get('/set-status', setStatus(app, io))

lib/setStatus.js

const getStatus = require('./getStatus.js')

module.exports = (app, io) => {
  return (req, res) => {
    const { id, value } = req.query // id is in this example '1'
    req.app.locals['target' + id].pwmWrite(value))
    getStatus(app, io)
    res.send({ value }) // don't need this
  }
}

lib/getStatus.js

const pins = require('../config.js').pins

module.exports = async (app, socket) => {
  const res = []
  pins.map((p, index) => {
    res.push(app.locals['target' + (index + 1)].getPwmDutyCycle())
  })
  socket.emit('gpioStatus', res)
}

所以首先我不确定，如果我正确地拆分了该代码，请考虑进行单元测试。

对我来说，唯一需要通过调用/set-status?id=1&value=50来完成的事情就是为一个(我猜)对象调用pwmWrite()，该对象由new Gpio定义并存储在expressJS的locals中。

第二点:如果这是正确的方法，我不明白如何编写jestJS单元测试来检查是否已调用pwmWrite-这是在异步函数内部。

这是我的尝试，但是我无法测试pwmWrite的内部调用:

test('should call pwmWrite() and getStatus()', async () => {
  const app = {}
  const io = { emit: jest.fn() }
  const req = {
    app: {
      locals: {
        target1: { pwmWrite: jest.fn() }
        }
      }
    }
  }
  expect.assertions(1)
  expect(req.app.locals.target1.pwmWrite).toHaveBeenCalled()
  await expect(getStatus(app, io)).toHaveBeenCalled()
})

最佳答案

您非常亲密，只是缺少了一些东西。

您需要在Expect语句之前调用setStatus和getStatus方法，
并且您缺少req.query和res上的模拟，因为getStatus使用了它们。

test('should call pwmWrite() and getStatus()', async () => {
  const app = {}
  const io = {};
  const req = {
    query: {
      id: '1',
      name: 'foo'
    },
    app: {
      locals: {
          target1: { pwmWrite: jest.fn() }
      }
    }
  };
  const res = { send: jest.fn() };

  // Mock getStatus BEFORE requiring setStatus
  jest.mock('./getStatus');

  //OBS Use your correct module paths
  const setStatus = require('./setStatus');
  const getStatus = require('./getStatus');


  // Call methods
  setStatus(app, io)(req, res);

  expect.assertions(2);

  // Get called in setStatus
  expect(req.app.locals.target1.pwmWrite).toHaveBeenCalled();

  // See if mocked getStatus has been called
  await expect(getStatus).toHaveBeenCalled();
});

在需要getStatus之前，需要对setStatus进行模拟，因为在那里使用了ojit_code

关于javascript - expressJS/jestJS : How to split get() function to write simple jest unit test?，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/52842582/