10.4Authentication State Reuse

Logging in through the UI for every test is slow. Playwright's storageState lets you authenticate once and reuse the session across tests.

// auth.setup.ts — runs once before all tests
import { test as setup } from '@playwright/test';

setup('authenticate', async ({ page }) => {
  await page.goto('/login');
  await page.getByLabel('Email').fill('test@example.com');
  await page.getByLabel('Password').fill('password');
  await page.getByRole('button', { name: 'Sign in' }).click();
  await page.waitForURL('/dashboard');

  // Save authentication state (cookies + localStorage)
  await page.context().storageState({ path: '.auth/user.json' });
});

// playwright.config.ts
export default defineConfig({
  projects: [
    { name: 'setup', testMatch: /.*\.setup\.ts/ },
    {
      name: 'tests',
      dependencies: ['setup'],
      use: { storageState: '.auth/user.json' },
    },
  ],
});

Now all tests in the tests project start already logged in — no login UI interaction per test.