Gleb Bahmutov, PhD

VP of Engineering

End-to-end testing is fast and easy with

our planet is in imminent danger

https://lizkeogh.com/2019/07/02/off-the-charts/

+3 degrees Celsius will be the end.

we have to act today

ME

you

you

you

you

vote & lobby & rebel

if I can help I will

@bahmutov

gleb.bahmutov@gmail.com

If there is a company that fights global climate catastrophe and needs JavaScript and testing skills - I will do for free.

Dr Gleb Bahmutov PhD

C / C++ / C# / Java / CoffeeScript / JavaScript / Node / Angular / Vue / Cycle.js / functional

(these slides)

30 people. Atlanta, Philly, Boston, NYC, the world

Fast, easy and reliable testing for anything that runs in a browser

Quality software behaves the way users expect it to behave

We going to need some tests

E2E

integration

unit

Testing Pyramid △

E2E

integration

unit

Smallest pieces

Testing Pyramid △

Unit tests pass...

E2E

integration

unit

Component

E2E

integration

unit

Website / API

E2E

integration

unit

Really important to users

Really important to developers

E2E

integration

unit

Web application

  • Open real browser
  • Load actual app
  • Interact with app like a real user
  • See if it works
$ npm install -D cypress

Cypress demo

  • Typical test
  • Failing test
  • Recording tests
  • CI setup
  • Cypress dashboard
// ui-spec.js
it('loads the app', () => {
  cy.visit('http://localhost:3000')
  cy.get('.todoapp').should('be.visible')
})

Mocha BDD syntax

Chai assertions

it('adds 2 todos', () => {
  cy.visit('http://localhost:3000')
  cy.get('.new-todo')
    .type('learn testing{enter}')
    .type('be cool{enter}')
  cy.get('.todo-list li')
    .should('have.length', 2)
})
$ npx cypress open

DOM

storage

location

cookies

Cypress tests run in the same browser

DOM

storage

location

cookies

Cypress acts as a proxy for your app

Cypress Philosophy

  • Test your app

  • Stub 3rd party services

Tutorials

Api

Examples

  • "cypress open" - GUI interactive mode

  • "cypress run" - headless mode

Cypress CLI has 2 main commands

full video of the run, screenshots of every  failure

  • Every CI should be good

  • Or use a Docker image we provide

Running E2E on CI

Making it easy for users is not easy

Paid Features 💵

  • recording test artifacts
  • test parallelization
  • GitHub integration
  • (WIP) historical insights

Paid Features 💵

Paid Features 💵: artifacts

test output, video, screenshots

I have 100s of tests ...

$ npx cypress run --record --parallel

Cypress v3.1.0

Spin N CI machines and

Text

cypress-dashboard parallelization

cypress-dashboard parallelization

# machines run duration time savings
1 22:50 ~
2 11:47 48%
3 7:51 65%
4 5:56 74%
6 3:50 83%
8 3:00 87%
10 2:19 90%

cypress-dashboard parallelization

10 machines = 10x speed up

For React users

import { HelloState } from '../src/hello-x.jsx'
import React from 'react'
it('changes state', () => {
  cy.mount(<HelloState />)
  cy.contains('Hello Spider-man!')
  const stateToSet = { name: 'React' }
  cy.get(HelloState).invoke('setState', stateToSet)
  cy.get(HelloState)
    .its('state')
    .should('deep.equal', stateToSet)
  cy.contains('Hello React!')
})

Code Coverage

For React users

$ npm i -D @cypress/instrument-cra
+ @cypress/instrument-cra@1.0.0

"start": "react-scripts -r @cypress/instrument-cra start"

Visual testing

it('draws pizza correctly', function () {
  cy.percySnapshot('Empty Pizza')

  cy.enterDeliveryInformation()
  const toppings = ['Pepperoni', 'Chili', 'Onion']
  cy.pickToppings(...toppings)

  // make sure the web app has updated
  cy.contains('.pizza-summary__total-price', 'Total: $12.06')
  cy.percySnapshot(toppings.join(' - '))
})

Visual review workflow

<style type="text/css">
  .st0{fill:#FFD8A1;}
  .st1{fill:#E8C08A;}
- .st2{fill:#FFDC71;}
+ .st2{fill:#71FF71;}
  .st3{fill:#DFBA86;}
</style>

changes crust color SVG

1. Make pull request with visual changes

Visual review workflow

catch visual changes in the pull request

2. Review & approve visual changes

Visual review workflow

2. Review & approve visual changes

App Actions

// app code
var model = new app.TodoModel('react-todos')
if (window.Cypress) {
  window.model = model
}
// test code
export const addTodos = (...todos) => {
  cy.window()
    .its('model')
    .should('be.an', 'object')
    .invoke('addTodo', ...todos)
}

Why developers love Cypress

  • Fast, flake-free

  • GUI, time travel

  • Test recording

  • Documentation

Coming soon

  • Retries / flake factor

  • Cross-browser

  • Full network stubbing

  • so many more ideas ...

IE11

Thank you 👏

@cypress_io

@bahmutov

End-to-end testing is fast and easy with Cypress.io

By Gleb Bahmutov

End-to-end testing is fast and easy with Cypress.io

Unit testing is hard and time-consuming; and worse - the users and the customers do not care! They only want the features working in the production system, everything else is development overhead. If this is the case, how do we improve web application quality? How do we catch the bugs early? How can we test the deployed system effectively? This presentation tries to answer many of these questions in a web framework agnostic way using open source test runner Cypress.io.

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