Overview of the Nx Playwright Plugin

Playwright is a modern web test runner. With included features such as:

• Cross browser support, including mobile browsers
• Multi tab, origin, and user support
• Automatic waiting
• Test generation
• Screenshots and videos

Setting Up @nx/playwright

Installation

Keep Nx Package Versions In Sync

Make sure to install the @nx/playwright version that matches the version of nx in your repository. If the version numbers get out of sync, you can encounter some difficult to debug errors. You can fix Nx version mismatches with this recipe.

In any Nx workspace, you can install @nx/playwright by running the following command:

nx add @nx/playwright

This will install the correct version of @nx/playwright.

How @nx/playwright Infers Tasks

The @nx/playwright plugin will create a task for any project that has a Playwright configuration file present. Any of the following files will be recognized as a Playwright configuration file:

• playwright.config.js
• playwright.config.ts
• playwright.config.mjs
• playwright.config.mts
• playwright.config.cjs
• playwright.config.cts

View Inferred Tasks

To view inferred tasks for a project, open the project details view in Nx Console or run nx show project my-project --web in the command line.

@nx/playwright Configuration

The @nx/playwright/plugin is configured in the plugins array in nx.json.

nx.json

{
  "plugins": [
    {
      "plugin": "@nx/playwright/plugin",
      "options": {
        "ciTargetName": "e2e-ci",
        "targetName": "e2e"
      }
    }
  ]
}

The targetName and ciTargetName options control the name of the inferred Playwright tasks. The default names are e2e and e2e-ci.

Splitting E2E Tests

@nx/playwright/plugin leverages Nx Atomizer to split your e2e tests into smaller tasks in a fully automated way. This allows for a much more efficient distribution of tasks in CI. You can read more about the Atomizer feature here.

If you would like to disable Atomizer for Playwright tasks, set ciTargetName to false.

E2E Testing

By default, when creating a new frontend application, Nx will prompt for which e2e test runner to use. Select playwright or pass in the arg --e2eTestRunner=playwright

nx g @nx/web:app apps/frontend --e2eTestRunner=playwright

Add Playwright e2e to an existing project

To generate an E2E project for an existing project, run the following generator

nx g @nx/playwright:configuration --project=your-app-name

Optionally, you can use the --webServerCommand and --webServerAddress option, to auto setup the web server option in the playwright config

nx g @nx/playwright:configuration --project=your-app-name --webServerCommand="npx serve your-project-name" --webServerAddress="http://localhost:4200"

Testing Applications

Run nx e2e <your-app-name> to execute e2e tests with Playwright

Selecting Specific Specs

You can use the --grep/-g flag to filter tests using regular expressions. You can use the --grepInvert/-gv flag to filter out tests that match the regular expression.

# run tests that match the regular expression
nx e2e frontend-e2e --grep="feat-a"

# run tests that don't match the regular expression
nx e2e frontend-e2e --grepInvert="feat-a"

By default, Playwright will run in headless mode. You will have the result of all the tests and errors (if any) in your terminal. Test output such as reports, screenshots and videos, will be accessible in dist/.playwright/apps/<your-app-name>/. This can be configured with the outputDir configuration options.

Output Caching

If changing the output directory or report output, make sure to update the target outputs so the artifacts are correctly cached

Watching for Changes

With, nx e2e frontend-e2e --ui Playwright will start in headed mode where you can see your application being tested.

From, there you can toggle on the watch icon which will rerun the tests when the spec file updates.

nx e2e <your-app-name> --ui

You can also use --headed flag to run Playwright where the browser can be seen without using the Playwright UI

Specifying a Project/Target Browser

The default generated Playwright configuration will contain a projects property that contains a list of browsers to run the tests against.

It should look similar to this:

export default defineConfig({
  ...,
  projects: [
    {
      name: "chromium",
      use: { ...devices["Desktop Chrome"] },
    },

    {
      name: "firefox",
      use: { ...devices["Desktop Firefox"] },
    },

    {
      name: "webkit",
      use: { ...devices["Desktop Safari"] },
    }
  ]
});

By default, Playwright will run tests against all browsers in the projects list.

You can specify a specific browser to run the tests against by passing the --project flag to the nx e2e command.

nx e2e frontend-e2e -- --project=firefox

Argument Forwarding

As Nx also has a --project argument, you need to use -- to forward the argument to the Playwright configuration.

Specifying a Base Url

The baseURL property within the Playwright configuration can control where the tests visit by default.

import { defineConfig } from '@playwright/test';

export default defineConfig({
  // Rest of your config...

  // Run your local dev server before starting the tests
  webServer: {
    command: 'npx serve <your-app-name>',
    url: 'http://localhost:4200',
    reuseExistingServer: !process.env.CI,
  },
  use: {
    baseURL: 'http://localhost:4200', // url playwright visits with `await page.goto('/')`;
  },
});

In order to set different baseURL values for different environments you can pass them via the environment variables and nx configurations or optionally via setting them per the environment they are needed in such as CI

import { defineConfig } from '@playwright/test';

const baseUrl =
  process.env.BASE_URL ?? process.env.CI
    ? 'https://some-staging-url.example.com'
    : 'http://localhost:4200';

export default defineConfig({
  // Rest of your config...

  // Run your local dev server before starting the tests
  webServer: {
    command: 'npx serve <your-app-name>',
    url: baseUrl,
    reuseExistingServer: !process.env.CI,
  },
  use: {
    baseURL: baseUrl, // url playwright visits with `await page.goto('/')`;
  },
});

By default Nx, provides a nxE2EPreset with predefined configuration for Playwright.

import { defineConfig } from '@playwright/test';
import { nxE2EPreset } from '@nx/playwright/preset';
import { workspaceRoot } from '@nx/devkit';

// For CI, you may want to set BASE_URL to the deployed application.
const baseURL = process.env['BASE_URL'] || 'http://localhost:4200';

/**
 * Read environment variables from file.
 * https://github.com/motdotla/dotenv
 */
// require('dotenv').config();

/**
 * See https://playwright.dev/docs/test-configuration.
 */
export default defineConfig({
  ...nxE2EPreset(__filename, { testDir: './e2e' }),
  /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
  use: {
    baseURL,
    /* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
    trace: 'on-first-retry',
  },
  /* Run your local dev server before starting the tests */
  webServer: {
    command: 'npx nx serve <your-app-name>',
    url: baseURL,
    reuseExistingServer: !process.env.CI,
    cwd: workspaceRoot,
  },
});

This preset sets up the outputDir and HTML reporter to output in dist/.playwright/<path-to-project-root> and sets up chromium, firefox, webkit browsers to be used a browser targets. If you want to use mobile and/or branded browsers you can pass those options into the preset function

export default defineConfig({
  ...nxE2EPreset(__filename, {
    testDir: './e2e',
    includeMobileBrowsers: true, // includes mobile Chrome and Safari
    includeBrandedBrowsers: true, // includes Google Chrome and Microsoft Edge
  }),
  // other settings
});

If you want to override any settings within the nxE2EPreset, You can define them after the preset like so

const config = nxE2EPreset(__filename, {
  testDir: './e2e',
  includeMobileBrowsers: true, // includes mobile Chrome and Safari
  includeBrandedBrowsers: true, // includes Google Chrome and Microsoft Edge
});
export default defineConfig({
  ...config
  retries: 3,
  reporters: [...config.reporters, /* other reporter settings */],
});

See the Playwright configuration docs for more options for Playwright.