Node.js
Quadri di test unitari

Mocha sincrono

describe('Suite Name', function() {
  describe('#method()', function() {
    it('should run without an error', function() {
      expect([ 1, 2, 3 ].length).to.be.equal(3)
    })
  })
})

Mocha asincrono (callback)

var expect = require("chai").expect;
describe('Suite Name', function() {
  describe('#method()', function() {
    it('should run without an error', function(done) {
      testSomething(err => {
        expect(err).to.not.be.equal(null)
        done()
      })
    })
  })
})

Mocha asincrono (Promessa)

describe('Suite Name', function() {
  describe('#method()', function() {
    it('should run without an error', function() {
      return doSomething().then(result => {
         expect(result).to.be.equal('hello world')
      })
    })
  })
})

Mocha asincrono (async / await)

const { expect } = require('chai')

describe('Suite Name', function() {
  describe('#method()', function() {
    it('should run without an error', async function() {
      const result = await answerToTheUltimateQuestion()
      expect(result).to.be.equal(42)
    })
  })
})