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Fast Intro software testing

  • Unit Testing: Test each piece individually (like checking each piece of a puzzle).
  • Integration Testing: Make sure the pieces work well together.
  • E2E (End-to-End) testing: Test the final product to see if it meets expectations (like looking at the complete puzzle).

Unit Testing​

Tools: Jest

Facility :​

npm install --save-dev jest

Example with Jest​

Suppose you have a simple add function in add.js

function add(a, b) {
  return a + b;
}
module.exports = add;

Create a test file add.test.js

const add = require('./add');

test('adds 1 + 2 to equal 3', () => {
  expect(add(1, 2)).toBe(3);
});

Run Tests​

Add a script in your package.json

"scripts": {
  "test": "jest"
}

Then run with:

npm test

Ultimately, automate the tests at each commit, for example, to ensure that the code does not break the tests.

Integration Test (tests the interactions between the different parts of the application)​

E2E test (simulates a complete real user experience)​

Tools: Cypress

Facility :​

npm install cypress --save-dev

Example with Cypress​

Create a test file add.test.js

describe('Login Test', () => {
  it('Logs in successfully', () => {

    cy.visit('http://localhost:3000/login');

    cy.get('input[name="username"]').type('user_test');
    cy.get('input[name="password"]').type('password123');

    cy.get('button[type="submit"]').click();

    cy.url().should('include', '/home');
    cy.contains('Bienvenue, user_test');
  });
});

What we are testing here:​

  • Opens the login page.
  • Populates form fields with test IDs.
  • Submits the form.
  • Checks if the URL has changed to the home page and if a welcome message is displayed.

Run Tests​

npx cypress open