cypress

What is cypress?

Cypress is a next-generation front end testing tool built for the modern web. It is a feature-rich end-to-end testing framework that makes testing anything that runs in a browser easier. Cypress provides a robust, complete framework for running automated tests on web applications.

What are cypress's main functionalities?

End-to-End Testing

Cypress can be used to perform end-to-end testing on web applications. The code sample demonstrates how to visit a webpage, interact with elements, and assert that the actions have the expected outcome.

cy.visit('https://example.com')
  .get('.new-todo')
  .type('Learn Cypress{enter}')
  .get('.todo-list li')
  .should('have.length', 1)

Integration Testing

Cypress can also be used for testing React components by mounting them in the test runner. The code sample shows how to mount a component, simulate user interaction, and assert the result.

cy.mount(<MyComponent />)
  .get('button').click()
  .get('.result').should('contain', 'Clicked')

API Testing

Cypress can perform API testing by sending HTTP requests and asserting the responses. The code sample demonstrates how to send a POST request to an API endpoint and validate the response.

cy.request('POST', '/api/items', { name: 'Cypress' })
  .then((response) => {
    expect(response.body).to.have.property('id')
    expect(response.body).to.have.property('name', 'Cypress')
  })

Visual Testing

With the help of plugins, Cypress can be extended to perform visual regression testing. The code sample shows how to take a snapshot of an element and compare it to a baseline image for visual differences.

cy.visit('https://example.com')
  .get('.important-element')
  .matchImageSnapshot()

Other packages similar to cypress

selenium-webdriver

Selenium WebDriver is one of the most popular browser automation tools. It supports multiple browsers and programming languages. Compared to Cypress, Selenium tests can be slower and more flaky due to reliance on a separate server (Selenium Server) and the need to manage browser drivers.

puppeteer

Puppeteer is a Node library which provides a high-level API to control Chrome or Chromium over the DevTools Protocol. It is typically faster than Selenium and can be used for both end-to-end testing and web scraping. Unlike Cypress, Puppeteer only works with Chrome/Chromium, while Cypress supports multiple browsers.

playwright

Playwright is a Node library to automate the Chromium, WebKit, and Firefox browsers with a single API. It is similar to Puppeteer but provides cross-browser support. Playwright offers more features out of the box compared to Cypress, such as native mobile emulation.

testcafe

TestCafe is a Node.js tool to automate end-to-end web testing. It is easy to set up and does not require WebDriver. TestCafe runs on multiple browsers and operating systems and can execute tests concurrently. It is a good alternative to Cypress with a different set of trade-offs, particularly in terms of test speed and debugging capabilities.

README

cypress

Testing the way it should be

Install

Requires Node version >= 0.12

npm install --save-dev cypress

Open Cypress desktop GUI application

To open Cypress app, there are two alternatives from the command line

./node_modules/.bin/cypress open
$(npm bin)/cypress open

or you can add new a script to your package.json

{
  "scripts": {
    "open": "cypress open"
  }
}

and then call npm run open

Run tests

To run e2e tests in headless mode execute $(npm bin)/cypress run

Load Cypress as an NPM module

const cy = require('cypress')
// opens desktop GUI application and returns a promise
cy.open(options)
// runs e2e tests in headless browser
// and returns a promise with test results
cy.run(options).then(results, console.error)