Introducing sinon

sinon is used to test spies, stubs, and mocks for JavaScript tests. To learn about these, let's move on to the movie rating application we have in our controller file, controller/movies.js:

const Movie = require("../models/Movie");
const passport = require("passport");

module.exports.controller = (app) => {
  // fetch all movies
  app.get("/movies", function(req, res) {
    Movie.find({}, 'name description release_year genre', function 
    (error, movies) {
      if (error) { console.log(error); }
       res.send({
        movies: movies
      })
    })
  })

  // add a new movie
  app.post('/movies', (req, res) => {
    const movie = new Movie({
      name: req.body.name,
      description: req.body.description,
      release_year: req.body.release_year,
      genre: req.body.genre
    })

    movie.save(function (error, movie) {
      if (error) { console.log(error); }
      res.send(movie)
    })
  })
}               

In the preceding code, each API call needs...