Effective E2E and Integration Testing with Cypress

Nikola Đuza

Writer and owner at Pragmatic Pineapple

Sr Software Engineer at ToptalΒ πŸ–₯

Cypress.io Ambassador

Novi Sad JS Organizer πŸ—£

Ruby and JS πŸ’Ž

What will you learn?

  • Difference between Selenium, Puppeteer, and Cypress
  • Cypress Best Practices
  • Advanced use of Cypress

Topics

  • Why test?
  • What about code coverage?
  • What kinds of tests to write?
  • Cypress VS Selenium VS Puppeteer
  • Cypress Best Practices
  • Cypress + React = πŸ’“
  • GIFT 🎁

Why test?

Why test?

  • Make sure software works
  • And that it will work
  • Future proof

Why test?

CONFIDENCE

Why test?

Why test?

Why test?

BE SURE TO

TEST YOUR CODE

What about code coverage?

Code coverage

Code coverage

Code coverage

How much is enough?

Code coverage

How much is enough?

Β―\_(ツ)_/Β―

Code coverage

How much is enough?

Β―\_(ツ)_/Β― IT DEPENDS

Code coverage

YOU SHOULD HAVE IT

What kinds of tests to write?

The "Smoking" Testing Pyramid

The Testing Square

The Testing Trophy

Static tests (analysis)

TypeScript

ESLint

Static tests (analysis)

Check out

Unit tests

Integration tests

E2E tests

Unit and integration and E2E tests

Cypress VS Selenium VS Puppeteer

What are they?

Browser automating tools 🌍

Selenium VS Puppeteer VS Cypress

Selenium

  • Initial idea 2004 by Jason Huggins

  • You can cure mercury poisoning by taking selenium supplements

Selenium

Selenium

Supports: Java, C#, JavaScript, Python, Ruby, Objective-C

Selenium

Supports almost all browsers

Selenium

  • First commit in 2017
  • Founded by Google
  • Node.js library for controlling Chrome

Puppeteer

Puppeteer

Uses DevTools protocol

Puppeteer

Uses DevTools protocol

Puppeteer

Supports writing tests in JavaScript

Puppeteer

Supports Chrome and Firefox

Puppeteer

Puppeteer

Cons:

  • No built-in tooling
  • Only Chrome and Firefox
  • Parallel builds on CI is difficult
  • Started in 2015 Brian Mann and Randall KentΒ 
  • Testing framework
  • Runs inside the browser

Cypress

Cypress

Cypress

Supports writing tests in JavaScript

Cypress

Cypress

Supports: Chrome-based browsers, Firefox, Edge

Cypress

Cypress

Cons:

  • Can't drive two browsers at the same time
  • No multi-tab support
  • No Safari and IE support (but are in consideration)
  • Limited support for iFrames

Cypress

Cypress

Show us the tests already

Cypress Best Practices

Cypress Best Practices

Test login flow

Cypress Best Practices

Test login flow

BUT

ONLY ONCE

Login test example

Login test example

Viewing the settings page

Viewing the settings page

Login without UI test example

Page Object pattern

Page Object pattern

Cypress Custom Commands

Adding a Cypress Custom Command

Login without UI test example

Testing Login Flow only once

gives you

  • More speed 🏎
  • Testing in isolation πŸ•
  • Less complex tests πŸ’†β€β™€οΈ

Cypress Best Practices

DO NOT USE

UI

TO POPULATE DATA

Cypress Best Practices

CLEAN UP STATE

BEFORE

TESTS RUN

Selenium-based tools

In Cypress

There's no guarentee this will run

Clean up state before tests run

Cypress Best Practices

START A WEB SERVER PRIOR TO RUNNING CYPRESS

Start a web server prior to running Cypress

$ npm start & cypress run

Start a web server prior to running Cypress

πŸ™…β€β™€οΈπŸ›‘βœ‹πŸ™…β€β™€οΈ

$ npm start & cypress run

Start a web server prior to running Cypress

$ npm start & cypress run

πŸ™…β€β™€οΈπŸ›‘βœ‹πŸ™…β€β™€οΈ

$ npm start & wait-on http://localhost:8080 \
	    & cypress run

Start a web server prior to running Cypress

$ npm test

Cypress Best Practices

Check out more at:

Cypress + React = ❀️

Snapshot testing

Snapshot testing

HTML

Snapshot testing

JSON response

Redux

exposing the store

Redux

dispatching action objects

Redux

dispatching actions from our code

Redux + Snapshots

checking state with snapshot testing

React Unit Tests

React Unit Tests

File upload

File upload

BUT WAIT βœ‹

BUT WAIT βœ‹

Β 

YOU JUST STUBBED

A SERVER RESPONSE

BUT WAIT βœ‹

Β 

YOU JUST STUBBED

A SERVER RESPONSE

Β 

IT'S NOT A "TRUE" E2E TEST?! πŸ€”

STUBBING REQUESTS

REAL REQUESTS

Writing UI tests in Cypress

MEANS WRITING BOTH

  • E2E tests πŸ–πŸ”β›°

  • integration tests πŸ—»πŸ”„πŸ”

Testing Trophy

Testing Trophy

cheap

πŸ’΅πŸ’°

Testing Trophy

cheap

πŸπŸ’¨

🐒

πŸ’΅πŸ’°

Testing Trophy

cheap

πŸπŸ’¨

🐒

πŸ’΅πŸ’°

BIG PROBLEMS 🀯

Small problems 😌

Integration tests provide best balance of:

  • πŸ’΅
  • πŸπŸ’¨
  • 😌

That's why UI testing in Cypress is:

  • cheap πŸ’΅
  • fast πŸπŸ’¨
  • fun 😌
$ npm install cypress

Let's see it πŸ‘€

Gift time 🎁

Free Cypress shirt 🎁

❓More questions? Join Discord

https://pragmaticpineapple.com/discord

✍️ Check out my blog https://pragmaticpineapple.com

🦜 Follow me on Twitter https://twitter.com/nikolalsvk

Effective E2E and Integration Testing with Cypress

By Nikola Đuza

Effective E2E and Integration Testing with Cypress

Why and how to do (E2E and integration) tests with Cypress. There is also a focus on comparing Selenium to Cypress.

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