Version: v4.20

Playwright Overview

note

The Stencil Playwright adapter is currently an experimental package. Breaking changes may be introduced at any time.

The Stencil Playwright adapter is designed to only work with version 4.13.0 and higher of Stencil!

Playwright is an automated end-to-end testing framework built to run on all modern browser engines and operating systems. Playwright leverages the DevTools protocol to provide reliable tests that run in actual browsers.

Set Up

To add Playwright to an existing Stencil project, leverage the Stencil Playwright testing adapter. This is a tool built by the Stencil team to help Stencil and Playwright work better together. The best part is you'll write your tests using the same APIs as defined and documented by Playwright. So, be sure to check out their documentation for help writing your first tests!

To install the Stencil Playwright adapter in an existing Stencil project, follow these steps:

Install the necessary dependencies:

npm
Yarn
pnpm

npm i @stencil/playwright @playwright/test --save-dev

yarn add @stencil/playwright @playwright/test --dev

pnpm add @stencil/playwright @playwright/test --save-dev

Install the Playwright browser binaries:
```
npx playwright install
```
Create a Playwright config at the root of your Stencil project:
playwright.config.ts
```
import { expect } from '@playwright/test';
import { matchers, createConfig } from '@stencil/playwright';

// Add custom Stencil matchers to Playwright assertions
expect.extend(matchers);

export default createConfig({
  // Overwrite Playwright config options here
});
```
The createConfig() function is a utility that will create a default Playwright configuration based on your project's Stencil config. Read more about how to use this utility in the API docs.

note
For createConfig() to work correctly, your Stencil config must be named either stencil.config.ts or stencil.config.js.
update your project's tsconfig.json to add the ESNext.Disposable option to the lib array:
tsconfig.json
```
{
  lib: [
    ...,
    "ESNext.Disposable"
  ],
  ...
}
```
note
This will resolve a build error related to Symbol.asyncDispose. If this is not added, tests may fail to run since the Stencil dev server will be unable to start due to the build error.
Ensure the Stencil project has a www output target. Playwright relies on pre-compiled output running in a dev server to run tests against. When using the createConfig() helper, a configuration for the dev server will be automatically created based on the Stencil project's www output target config and dev server config. If no www output target is specified, tests will not be able to run.
Add the copy option to the www output target config:
stencil.config.ts
```
{
   type: 'www',
   serviceWorker: null,
   copy: [{ src: '**/*.html' }, { src: '**/*.css' }]
}
```
This will clone all HTML and CSS files to the www output directory so they can be served by the dev server. If you put all testing related files in specific directory(s), you can update the copy task glob patterns to only copy those files:
stencil.config.ts
```
{
   type: 'www',
   serviceWorker: null,
   copy: [{ src: '**/test/*.html' }, { src: '**/test/*.css' }]
}
```
note
If the copy property is not set, you will not be able to use the page.goto testing pattern!
Test away! Check out the e2e testing page for more help getting started writing tests.

Migrating to Playwright

If you are working in a Stencil project with an existing end-to-end testing setup via the Stencil Test Runner, you can continue using your existing e2e testing setup while sampling the Playwright adapter or migrating tests over time. To do so, there are two options:

Option 1: Update the Playwright config to match a different test file pattern:
playwright.config.ts
```
export default createConfig({
  // Example: match all test files with the 'e2e.playwright.ts' naming convention
  testMatch: '*.e2e.playwright.ts',
});
```
By default, the Playwright adapter will match all files with the '.e2e.ts' extension, which is the same pattern used by the Stencil test runner for e2e tests. See the PlaywrighttestMatch documentation for more information on acceptable values.

Changing this value is useful if you are just testing out Playwright, but haven't committed to migrating all test files.
Option 2: Update the Stencil Test Runner to match a different test file pattern:
stencil.config.ts
```
export config: Config = {
   ...,
   test: {
      // Stencil Test Runner will no longer execute any 'e2e.ts` files
      testRegex: '(/__tests__/.*|(\\.|/)(test|spec)|[//](e2e))\\.[jt]sx?$'
   }
}
```
Changing this value is useful if you intend on using Playwright as your main e2e testing solution and want to keep the 'e2e.ts` extension for test files.

tip

You could also separate tests into specific directories for each test runner and have the test patterns match only their respective directories.

In addition, Playwright will not execute as a part of the Stencil CLI's test command (i.e. stencil test --e2e). To have Playwright execute alongside the Stencil Test Runner, you'll need to include an explicit call to the Playwright CLI as a part of your project's package.json test script:

package.json
{
  "scripts": {
    "test.e2e": "stencil test --e2e && playwright test"
  }
}

Set Up​

Migrating to Playwright​

Contents

Set Up

Migrating to Playwright