Testing

Lab: Jest

In this course we use Jest for testing.

To get started, well... follow the instruction at the getting started page: https://jestjs.io/docs/en/getting-started.html

"scripts": {

   "test": "jest"

"jest": {

   "verbose": true,

   "collectCoverage": true

function concatenateStrings (a,b) {

    return a+b

module.exports = { conc: concatenateStrings}

const conc = require('./someModule').conc

test('multiply 2', () => {

    expect(4).toBe(4);

});

test('concat test', () => {

    expect(conc('a','b')).toBe('ab');

});

test('concat null', () => {

    expect(conc(null,null)).toBe(0);

});

const fetch = require("node-fetch")

test('fetch', () => {

  fetch("https://sites.google.com/unitn.it/seii-inf-org-unitn").then( (r) => {

    expect(r.status).toEqual(200)

})

})

This does not work because fetch is a non-blocking call.

test('fetch', done => {

...

  done()

const express = require('express')

var bodyParser = require('body-parser')

const app = express()

app.use( bodyParser.json() )

app.use( bodyParser.urlencoded({ extended: true }) )

const PORT = process.env.PORT || 3000

var courses_offered = [{id: 21, name: 'IS2'}, {id: 28, name:'sweng'}]

app.get('/courses', (req, res) => {

   res.json(courses_offered)

})

app.listen(PORT, () => console.log('App listening on port ' + PORT) )

const fetch = require("node-fetch");

const url = "http://localhost:3000/"

async function get(url) {

    console.log('getting ' + url)

    const response = await fetch(url)

    const json = await response.json()

    console.log(json)

    return json

get(url+'courses')

const fetch = require("node-fetch");

const url = "http://localhost:3000/courses"

it('works with get', async () => {

    expect.assertions(1)

    var response = await fetch(url)

    expect(response.status).toEqual(200)

})

We take selected chapters from the book on software testing, as described in this pdf document, accessible only with UNITN account. Specifically, here is what is required:
- Ch1: tutto
- Ch2, Ch3: come evidenziato
- Ch4: come evidenziato, incluso tutto il white-box testing
- Ch8: come evidenziato
(The entire book, called "The art of software testing", can be found online (I have seen some people posted PDFs for it) - again you are not required to read it all, only the parts as described above)
From jest, you are expected to know how to use jest to do write test cases, how to test asynch code, and how to perform setup and teardown. You are not expected to learn all matchers, but you should have a general idea of what they are and which kinds of matchers are avail. Basically, you should be familiar with all the "introduction" items (getting started - up to "Running from command line" excluded, using matchers, setup and teardown) - except testing asynch code and mock functions.
you should also know how to test for coverage with Jest

The best thing is to follow the entire Udacity classes on software testing and debugging
book "how google test software"

Exercises:

For the below,

Write the function,
write test cases for it, based on black box testing and equivalence partitioning and boundary analysis
write test cases to achieve 100% coverage

Function that computes the square root of a positive number
Function that receives four positive integers and returns if these integers can be the length of the sides of a rectangle.
Function that receives three positive integers and returns if these integers can be the length of the sides of a triangle, and also returns which kind of a triangle this is.

Given this function, achieve

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