Nodejs and NPM install on different platforms

const handlers = require('../handlers')

test('home page renders', () => {
  const req = {}
  const res = { render: jest.fn() }
  handlers.home(req, res)
  expect(res.render.mock.calls.length).toBe(1)
  expect(res.render.mock.calls[0][0]).toBe('home')
})
// the first array index specifies which invocation, and the second one specifies which argument

test('about page renders with fortune', () => {
  const req = {}
  const res = { render: jest.fn() }
  handlers.about(req, res)
  expect(res.render.mock.calls.length).toBe(1)
  expect(res.render.mock.calls[0][0]).toBe('about')
  expect(res.render.mock.calls[0][1])
    .toEqual(expect.objectContaining({
      fortune: expect.stringMatching(/\W/),
    }))
})

test('404 handler renders', () => {
  const req = {}
  const res = { render: jest.fn() }
  handlers.notFound(req, res)
  expect(res.render.mock.calls.length).toBe(1)
  expect(res.render.mock.calls[0][0]).toBe('404')
})

test('500 handler renders', () => {
  const err = new Error('some error')
  const req = {}
  const res = { render: jest.fn() }
  const next = jest.fn()
  handlers.serverError(err, req, res, next)
  expect(res.render.mock.calls.length).toBe(1)
  expect(res.render.mock.calls[0][0]).toBe('500')
})

To invoke our render, we need request and response objects. We’d be writing code all week if we wanted to simulate the whole request and response objects, but fortunately we don’t actually need much from them. We know that we don’t need anything at all from the request object in this case (so we just use an empty object), and the only thing we need from the response object is a render method. Note how we construct the render function: we just call a Jest method called jest.fn(). This creates a generic mock function that keeps track of how it’s called.

1. Starts our application server on an unoccupied port
2. Launches a headless Chrome browser and opens a page
3. Navigates to our application’s home page
4. Finds a link with data-test-id="about" to click it
5. Waits for the navigation to happen
6. Verifies that we are on the /about page


const portfinder = require('portfinder')
const puppeteer = require('puppeteer')

const app = require('../meadowlark.js')

let server = null
let port = null

beforeEach(async () => {
  port = await portfinder.getPortPromise()
  server = app.listen(port)
})

afterEach(() => {
  server.close()
})

test('home page links to about page', async () => {
  const browser = await puppeteer.launch()
  const page = await browser.newPage()
  await page.goto(`http://localhost:${port}`)
  await Promise.all([
    page.waitForNavigation(),
    page.click('[data-test-id="about"]'),
  ])
  expect(page.url()).toBe(`http://localhost:${port}/about`)
  await browser.close()
})