Advanced Topics

Service Workers

Playwright can register service workers in test context for PWA scenarios. route may intercept SW-controlled fetch depending on scope.

Test offline cache behavior with context.setOffline after SW precache.

• Clear service workers between tests to avoid cache bleed
• Wait for navigator.serviceWorker.ready before offline assertions
• Mock SW at network layer if full SW setup heavy

Authentication Flows

Beyond storageState, test OAuth by mocking token endpoint or using test IdP. Multi-factor flows may need TOTP seed in vault.

HTTP credentials for basic auth: use: { httpCredentials: { username, password } }.

await page.context().storageState({ path: "playwright/.auth/user.json" });

PDF Generation

page.pdf() generates PDF in headless Chromium—test report export features. Assert file size or text extraction with pdf-parse library outside browser.

Not supported in Firefox/WebKit projects.

await page.goto("/invoice/123");
await page.pdf({ path: "invoice.pdf", format: "A4" });

Accessibility Testing

Integrate @axe-core/playwright for automated a11y scans. expect(page).toPassAxe() or analyze per route in E2E suite.

Combine with getByRole-first locators—dual benefit resilient tests and a11y.

import AxeBuilder from "@axe-core/playwright";

const results = await new AxeBuilder({ page }).analyze();
expect(results.violations).toEqual([]);

Clock and Permissions

page.clock.install() mocks Date and timers for time-dependent UI—subscription expiry, countdown. grantPermissions for notifications, geolocation.

setGeolocation tests map features without real GPS.

await page.clock.install({ time: new Date("2024-06-01") });
await context.grantPermissions(["geolocation"]);