DOBROMIR HRISTOV

@d_m_hristov

MODERN E2E TESTING WITH

INTRODUCTION TO

Who am I ?

Dobromir Hristov

  • Lead FE Developer @Hypefactors
  • Article Author
  • Open Source Enthusiast

What is automated testing?

I

@d_m_hristov

I

What is automated testing?

Use a software tool to test another piece of software, comparing the actual outcomes against predicted outcomes.

What is automated testing?

@d_m_hristov

Why do people skip testing?

Too hard

Unexpected failing

Maintenance

Too much time

My code is just awesome

🦄

I

What is automated testing?

@d_m_hristov

Testing is hard

...

I

What is automated testing?

@d_m_hristov

I

When can we skip tests?

Why should we test?

Projects with little or no scope/end goal*

Quick, very short lifespan projects

@d_m_hristov

Well that was easy

@d_m_hristov

I

Best conditions for growing your own tests🌿

Why should we test?

  • Open Source - 100%
  • Complex applications with multiple external services
  • Projects involving large teams
  • Enterprise level applications - usually combine the above

@d_m_hristov

What types of tests are there?

I

Why should we test?

https://testingjavascript.com/

ESLint, Flow,
TS type check

Jest, Mocha, Jasmine, Ava

Nightwatch, TestCafe,
Puppeteer, Cypress

@d_m_hristov

State of End-to-end testing

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@d_m_hristov

What is End-to-End testing?

End-to-end testing is a methodology used to test whether the flow of an application or device is performing as designed from start to finish.

@d_m_hristov

@d_m_hristov

E2E testing before

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State of End-to-End testing

  • Finicky installation
  • Verbose syntax
  • Require abstractions
  • Hard to spy on requests
  • Often Java/Python based
  • Manual waiting for DOM updates
  • No access to in App state
  • Very slow

@d_m_hristov

II

State of End-to-End testing

  • Single command install
  • Easy to read & write tests
  • Test runner GUI
  • Flexible test organization
  • Outstanding CI integration
  • Extensive Docs

Free, Open Source, MIT License

@d_m_hristov

How to get started

1. Easy installation

npm install cypress && npx cypress open

2. Visit Awesome docs at docs.cypress.io 😍

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State of End-to-End testing

@d_m_hristov

If it ain't broke, don't fix it 🧐

  1. Familiar test organization
  2. Mocha, Chai, Sinon under the hood
  3. jQuery-like dom traversal 🤘🏻
  4. Lodash, Moment included

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State of End-to-End testing

describe('Checkout', () => {
  it('should add a pizza to the cart', () => {
    cy.visit('https://marcos-pizza.com')

    cy.get('h1')
      .should('contain', 'Choose your pizza')

    cy.get('.items > .item--pizza')
      .contains('pepperoni')
      .first()
      .click()

    cy.get('.cart .cart__items')
      .should('have.length', 1)

    cy.get('input.address-field')
      .type('My home street 1')

    cy.get('select.city')
      .select('sofia')
    
    cy.get('input.time')
      .type(Cypress.moment().hour(18).minute(30).toDate())

    cy.get('.cart .next')
      .click()
   
    cy.url().should('include','/cart')
  })
})

@d_m_hristov

The missing parts 🧩

  1. Easily extract functions
  2. In-App state access 🤯
  3. Run actions before tests
  4. Make async requests
  5. Custom global commands
  6. Request mock and spying
  7. Rerun tests on change
  8. Community plugins

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State of End-to-End testing

const getStore = () => cy.window().its('$app.$store')

describe('Checkout', () => {
  beforeEach(() => {
    cy.server()  
    cy.route('POST','/finish').as('sendPizzas')
  })

  it('should finish an order from cart', () => {
    cy.visit('https://marcos-pizza.com/cart')
    
    cy.request('/api/pizzas').its('responseBody').then(({ data }) => {
      const pepperoni = Cypress._.find(data, { 'name': 'Pepperoni' })
      
      cy.get('.cart-items').should('have.length', 0)
      
      getStore().invoke('dispatch', 'addToCart', pepperoni.id)      
    })

    cy.closeAdPopup()
    
    getStore().its('state.cart.items').should('have.length', 1)
    
    cy.getByTestId('CartComplete-Trigger').click()

    cy.wait('@sendPizzas')
      .its('status')
      .should('eql', 200)

    cy.contains('Your pizza is on its way')
  })
})

@d_m_hristov

The unique in action 🦄

  1. Test runner GUI 😵
  2. Time traveling 🤔
  3. Dom inspection 😳
  4. Before/After snapshots
  5. Async DOM action retry
  6. HTTP Spies and Mocks

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State of End-to-End testing

Little things that make us smile 🍩🍺

  1. Auto screenshot on fail
  2. Auto video generation
  3. Outstanding CI integration
  4. Lots of examples 🙌🏻

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State of End-to-End testing

5. FREE

@d_m_hristov

Cypress in Action

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State of End-to-End testing

@d_m_hristov

The yet to come

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State of End-to-End testing

  • Chromium Only - FF very soon
  • No native events
  • No mobile testing
  • No multiple tab support
  • Iframe is a bit wonky

@d_m_hristov

Advanced techniques

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State of End-to-End testing

  • Prototype in Cypress before API is ready
  • Integrate with CI or GitHub Actions
  • Visual testing and diffing with Percy.io
  • E2E test coverage
  • App Actions
  • Crawl your API to collect stubs
  • Testing API responses and schemas
  • Seeding your UI with data before tests

@d_m_hristov

DEMO TIME

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State of End-to-End testing

Find me at

dobromir-hristov

d_m_hristov

dobromir_hristov

dobromir-hristov

Dobromir Hristov

Thanks

Modern E2E testing with Cypress

By Dobromir Hristov

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Modern E2E testing with Cypress

Why testing in general, and how Cypress is a game changer.

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