Run your tests using Jest & Puppeteer ๐ชโจ
npm install --save-dev jest-puppeteer puppeteer jest
Requires Jest v22+ TypeScript users should additionally install
@types/puppeteer
,@types/jest-environment-puppeteer
and@types/expect-puppeteer
jest-puppeteer is an MIT-licensed open source project. It's an independent project with ongoing development made possible thanks to the support of these awesome backers. If you'd like to join them, please consider:
Gold Sponsors are those who have pledged $100/month and more to jest-puppeteer.
Update your Jest configuration:
{
"preset": "jest-puppeteer"
}
Use Puppeteer in your tests:
describe('Google', () => {
beforeAll(async () => {
await page.goto('https://google.com')
})
it('should display "google" text on page', async () => {
await expect(page).toMatch('google')
})
})
Most continuous integration platforms limit the number of threads one can use. If you have more than one test suite running puppeteer chances are that your test will timeout. This is because jest will try to run puppeteer in parallel and the CI platform won't be able to handle all the parallel jobs in time. A fix to this is to run your test serially when in a CI environment. Users have discovered that running test serially in such environments can render up to 50% of performance gains.
This can be achieved through the CLI by running:
jest --runInBand
Alternatively, you can set jest to use as a max number of workers the amount that your CI environment supports:
jest --maxWorkers=2
Writing integration test can be done using Puppeteer API but it can be complicated and hard because API is not designed for testing.
To make it simpler, expect-puppeteer API add some specific matchers if you make expectation on a Puppeteer Page.
Some examples:
// Assert that current page contains 'Text in the page'
await expect(page).toMatch('Text in the page')
// Assert that a button containing text "Home" will be clicked
await expect(page).toClick('button', { text: 'Home' })
// Assert that a form will be filled
await expect(page).toFillForm('form[name="myForm"]', {
firstName: 'James',
lastName: 'Bond',
})
Debugging tests can be hard sometimes and it is very useful to be able to pause tests in order to inspect the browser. Jest Puppeteer exposes a method jestPuppeteer.debug()
that suspends test execution and gives you opportunity to see what's going on in the browser.
await jestPuppeteer.debug()
Jest Puppeteer integrates a functionality to start a server when running your test suite. It automatically closes the server when tests are done.
To use it, specify a server section in your jest-puppeteer.config.js
.
// jest-puppeteer.config.js
module.exports = {
server: {
command: 'node server.js',
port: 4444,
},
}
Other options are documented in jest-dev-server.
Jest Puppeteer automatically detects the best config to start Puppeteer but sometimes you may need to specify custom options. All Puppeteer launch or connect options can be specified in jest-puppeteer.config.js
at the root of the project. Since it is JavaScript, you can use all the stuff you need, including environment.
The browser context can be also specified. By default, the browser context is shared. incognito
is available if you want more isolation between running instances. More information available in jest-puppeteer-environment readme
// jest-puppeteer.config.js
module.exports = {
launch: {
dumpio: true,
headless: process.env.HEADLESS !== 'false',
},
browserContext: 'default',
}
Jest Puppeteer exposes three new globals: browser
, page
, context
. If you want to avoid errors, you can add them to your .eslintrc.js
:
// .eslintrc.js
module.exports = {
env: {
jest: true,
},
globals: {
page: true,
browser: true,
context: true,
jestPuppeteer: true,
},
}
Jest Puppeteer use expect-puppeteer
as setupTestFrameworkScriptFile
. If you want to use expect-puppeteer
don't forget to add it in your custom setupTestFrameworkScriptFile
:
// setupTestFrameworkScriptFile.js
require('expect-puppeteer')
// Your custom setup
// jest.config.js
module.exports = {
// ...
setupTestFrameworkScriptFile: './setupTestFrameworkScriptFile.js',
}
Sometimes you want to use your own environment, to do that you can extend PuppeteerEnvironment
.
First, create your own js file for custom environment.
// custom-environment.js
const PuppeteerEnvironment = require('jest-environment-puppeteer')
class CustomEnvironment extends PuppeteerEnvironment {
async setup() {
await super.setup()
// Your setup
}
async teardown() {
// Your teardown
await super.teardown()
}
}
module.exports = CustomEnvironment
Then, assigning your js file path to the testEnvironment
property in your Jest configuration.
{
// ...
"testEnvironment": "./custom-environment.js"
}
Now your custom setup
and teardown
will be triggered before and after each test suites.
It is possible to create your own globalSetup
and globalTeardown
.
For this use case, jest-environment-puppeteer
exposes two methods: setup
and teardown
, so that you can wrap them with your own global setup and global teardown methods as the following example:
// global-setup.js
const { setup: setupPuppeteer } = require('jest-environment-puppeteer')
module.exports = async function globalSetup() {
await setupPuppeteer()
// Your global setup
}
// global-teardown.js
const { teardown: teardownPuppeteer } = require('jest-environment-puppeteer')
module.exports = async function globalTeardown() {
// Your global teardown
await teardownPuppeteer()
}
Then assigning your js file paths to the globalSetup
and globalTeardown
property in your Jest configuration.
{
// ...
"globalSetup": "./global-setup.js",
"globalTeardown": "./global-teardown.js"
}
Now your custom globalSetup
and globalTeardown
will be triggered once before and after all test suites.
You can find an example of create-react-app setup in this repository.
Give access to the Puppeteer Browser.
it('should open a new page', async () => {
const page = await browser.newPage()
await page.goto('https://google.com')
})
Give access to a Puppeteer Page opened at start (you will use it most of time).
it('should fill an input', async () => {
await page.type('#myinput', 'Hello')
})
Give access to a browser context that is instantiated when the browser is launched. You can control whether each test has its own isolated browser context using the browserContext
option in your jest-puppeteer.config.js
.
Helper to make Puppeteer assertions, see documentation.
await expect(page).toMatch('A text in the page')
// ...
Put test in debug mode.
- Jest is suspended (no timeout)
- A
debugger
instruction to Chromium, if Puppeteer has been launched with{ devtools: true }
it will stop
it('should put test in debug mode', async () => {
await jestPuppeteer.debug()
})
You can specify a jest-puppeteer.config.js
at the root of the project or define a custom path using JEST_PUPPETEER_CONFIG
environment variable.
launch
<[object]> All Puppeteer launch options can be specified in config. Since it is JavaScript, you can use all stuff you need, including environment.connect
<[object]> All Puppeteer connect options can be specified in config. This is an alternative tolaunch
config, allowing you to connect to an already running instance of Chrome.server
<[Object]> Server options allowed by jest-dev-server
// jest-puppeteer.config.js
module.exports = {
launch: {
dumpio: true,
headless: process.env.HEADLESS !== 'false',
},
server: {
command: 'node server.js',
port: 4444,
},
}
This example uses an already running instance of Chrome by passing the active web socket endpoint to connect
. This is useful, for example, when you want to connect to Chrome running in the cloud.
// jest-puppeteer.config.js
const wsEndpoint = fs.readFileSync(endpointPath, 'utf8')
module.exports = {
connect: {
browserWSEndpoint: wsEndpoint,
},
server: {
command: 'node server.js',
port: 4444,
},
}
Thanks to Fumihiro Xue for his great Jest example.
MIT