# Playwright

Playwright is a testing framework that allows you to run tests automatically in Chromium, Firefox, and WebKit environments using a single API. You can use it to **write E2E tests**.

To use Playwright in Modern.js, you need to install the dependencies first. You can run the following commands:

import { PackageManagerTabs } from '@theme';

<PackageManagerTabs command={{ npm: "npm init playwright", yarn: "yarn create playwright", pnpm: "pnpm create playwright" }} />

The above commands will automatically install Playwright dependencies and help you install and configure it in your project through a series of prompts, including adding a `playwright.config.ts` file.

:::info
Refer to the official Playwright documentation at [Install Playwright](https://playwright.dev/docs/intro#installation) for a more detailed guide.
:::

After creating with the default configuration, you can see the following files in your project:

```ts title="tests/example.spec.ts"
import { test, expect } from '@playwright/test';

test('has title', async ({ page }) => {
  await page.goto('https://playwright.dev/');

  // Expect a title "to contain" a substring.
  await expect(page).toHaveTitle(/Playwright/);
});

test('get started link', async ({ page }) => {
  await page.goto('https://playwright.dev/');

  // Click the get started link.
  await page.getByRole('link', { name: 'Get started' }).click();

  // Expects page to have a heading with the name of Installation.
  await expect(
    page.getByRole('heading', { name: 'Installation' }),
  ).toBeVisible();
});
```

This is the default test file. Now create some new pages and test them.

## Create E2E Tests

First, create two Modern.js pages.

```tsx title="routes/page.tsx"
import { Link } from '@modern-js/runtime/router';

const Index = () => (
  <div>
    <h1>Home</h1>
    <Link to="/about">About</Link>
  </div>
);

export default Index;
```

```tsx title="routes/about/page.tsx"
import { Link } from '@modern-js/runtime/router';

const Index = () => (
  <div>
    <h1>About</h1>
    <Link to="/">Home</Link>
  </div>
);

export default Index;
```

Next, add test cases to ensure the links on your pages work properly.

```ts title="tests/example.spec.ts"
import { test, expect } from '@playwright/test'

test('should navigate to the about page', async ({ page }) => {
  // Start from the index page (the baseURL is set via the webServer in the playwright.config.ts)
  await page.goto('http://localhost:8080/')
  // Find an element with the text 'About' and click on it
  await page.click('text=About')
  // The new URL should be "/about" (baseURL is used there)
  await expect(page).toHaveURL('http://localhost:8080/about')
  // The new page should contain an h1 with "About"
  await expect(page.locator('h1')).toContainText('About')
})
```

## Run Test Cases

Playwright requires your Modern.js server to be running. We recommend running your test cases under production builds; you can run `pnpm run build` and `pnpm run serve` to simulate the production environment locally.

```bash
info    Starting production server...

  > Local:    http://localhost:8080/
  > Network:  http://10.94.59.30:8080/
```

After the project is successfully built and running, you can run Playwright cases in another terminal by executing `npx playwright test`:

```bash
Running 3 tests using 3 workers
  3 passed (2.0s)

To open last HTML report run:

  npx playwright show-report
```