cypress-slow-down

Slow down your Cypress tests

Watch the introduction to this plugin in the video Slow Down Cypress Tests. For advanced usage, see the lessons in my Cypress Plugins course.

Install

Add this NPM package to your project

# install using NPM
$ npm i -D cypress-slow-down
# or install using Yarn
$ yarn add -D cypress-slow-down

Include the plugin and call its function from your spec or support file

// cypress/e2e/spec.cy.js
// https://github.com/bahmutov/cypress-slow-down
import { slowCypressDown } from 'cypress-slow-down'
// slow down each command by the default amount
// which is 1 second
slowCypressDown()

Options

You can control the delay before each command (in milliseconds)

// when calling the slowCypressDown function
slowCypressDown(1000)

You can also control the delay using the Cypress environment variable commandDelay.

// cypress.config.js
const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    env: {
      // https://github.com/bahmutov/cypress-slow-down
      commandDelay: 500,
    },
  },
})
// cypress/e2e/spec.cy.js
import { slowCypressDown } from 'cypress-slow-down'
slowCypressDown() // slows down each command by 500ms

You can set the optional logToConsole parameter to false to prevent the plugin from logging each delay to the console.

slowCypressDown(1000, false)

Disable the slow down

You can disable the default slowdown by using false. For example, from the command line you can pass the boolean value:

$ npx cypress run --env commandDelay=false

Or you can use the process (OS) environment variable

$ CYPRESS_commandDelay=false npx cypress run

Or you can use the cypress.config.js to disable the slowdown

// cypress.config.js
const { defineConfig } = require('cypress')

module.exports = defineConfig({
  e2e: {
    env: {
      // https://github.com/bahmutov/cypress-slow-down
      commandDelay: false,
    },
  },
})

Change the command delay from DevTools

Because this plugin uses cypress-plugin-config to read the command delay option, you can change its value or disable the plugin completely from the DevTools console using the command Cypress.setPluginConfigValue('commandDelay', <value>)

The re-run the tests by pressing the key "R" or clicking "Run All Tests" button.

Child commands

You can slow down a part of your test by using the custom dual commands cy.slowDown(ms) and cy.slowDownEnd().

// your spec file
// cypress/e2e/spec.cy.js
// https://github.com/bahmutov/cypress-slow-down
import { slowCypressDown } from 'cypress-slow-down'
// registers the cy.slowDown and cy.slowDownEnd commands
import 'cypress-slow-down/commands'
// must enable the plugin using slowCypressDown
// can disable the slow down by default or use some default delay
slowCypressDown(false)

it('runs the middle part slowly', () => {
  cy.visit('/')
  cy.get('...').should('...').slowDown(1000)
  // these commands have 1 second delay
  ...
  cy.slowDownEnd()
  // back to the normal speed
})

Tip: to see how the commands are slowed down you can use the cypress-timestamps plugin.

Small print

Author: Gleb Bahmutov <[e-mail]> © 2022

• @bahmutov
• glebbahmutov.com
• blog
• videos
• presentations
• cypress.tips
• Cypress Tips & Tricks Newsletter
• my Cypress courses

License: MIT - do anything with the code, but don't blame me if it does not work.

Support: if you find any problems with this module, email / tweet / open issue on Github