feat: add e2e test cursor skill

2026-05-13 17:52:38 +02:00 · 2026-05-04 13:54:13 +05:30 · 2026-05-04 13:54:13 +05:30 · 4ac994792b
commit 4ac994792b
parent 2e1b9b5582
45 changed files with 39848 additions and 0 deletions
--- a/.cursor/skills/playwright-testing/service-workers-and-pwa.md
+++ b/.cursor/skills/playwright-testing/service-workers-and-pwa.md
@ -0,0 +1,524 @@
+# Service Workers and PWA Testing
+
+> **When to use**: When your application is a Progressive Web App (PWA) or uses service workers for offline support, caching, push notifications, or background sync.
+> **Prerequisites**: [core/configuration.md](configuration.md), [core/assertions-and-waiting.md](assertions-and-waiting.md)
+
+## Quick Reference
+
+```typescript
+// Service workers require a persistent context — use launchPersistentContext
+const context = await chromium.launchPersistentContext(userDataDir, {
+  baseURL: 'https://localhost:3000',
+});
+
+// Enable/disable offline mode
+await context.setOffline(true);   // Go offline
+await context.setOffline(false);  // Come back online
+
+// Wait for service worker to register
+const sw = await context.waitForEvent('serviceworker');
+console.log('SW URL:', sw.url());
+```
+
+## Patterns
+
+### Service Worker Registration
+
+**Use when**: You need to verify that your service worker registers successfully, activates, and controls the page.
+**Avoid when**: Your app does not use service workers.
+
+Service workers require a persistent browser context because they are tied to a profile. The default `page` fixture uses a temporary context that does not persist service worker registrations across navigations reliably.
+
+**TypeScript**
+```typescript
+import { test as base, expect, chromium, BrowserContext } from '@playwright/test';
+import path from 'path';
+import fs from 'fs';
+
+// Create a fixture with a persistent context for SW testing
+const test = base.extend<{ swContext: BrowserContext }>({
+  swContext: async ({}, use) => {
+    const userDataDir = path.join(__dirname, '.tmp-profile');
+    const context = await chromium.launchPersistentContext(userDataDir, {
+      baseURL: 'https://localhost:3000',
+    });
+    await use(context);
+    await context.close();
+    fs.rmSync(userDataDir, { recursive: true, force: true });
+  },
+});
+
+test('service worker registers and activates', async ({ swContext }) => {
+  const page = await swContext.newPage();
+
+  // Listen for the service worker event
+  const swPromise = swContext.waitForEvent('serviceworker');
+
+  await page.goto('/');
+
+  const sw = await swPromise;
+  expect(sw.url()).toContain('service-worker.js');
+
+  // Verify the SW is controlling the page
+  const isControlled = await page.evaluate(() => {
+    return navigator.serviceWorker.controller !== null;
+  });
+  expect(isControlled).toBe(true);
+});
+```
+
+**JavaScript**
+```javascript
+const { test: base, expect, chromium } = require('@playwright/test');
+const path = require('path');
+const fs = require('fs');
+
+const test = base.extend({
+  swContext: async ({}, use) => {
+    const userDataDir = path.join(__dirname, '.tmp-profile');
+    const context = await chromium.launchPersistentContext(userDataDir, {
+      baseURL: 'https://localhost:3000',
+    });
+    await use(context);
+    await context.close();
+    fs.rmSync(userDataDir, { recursive: true, force: true });
+  },
+});
+
+test('service worker registers and activates', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  const swPromise = swContext.waitForEvent('serviceworker');
+
+  await page.goto('/');
+
+  const sw = await swPromise;
+  expect(sw.url()).toContain('service-worker.js');
+
+  const isControlled = await page.evaluate(() => {
+    return navigator.serviceWorker.controller !== null;
+  });
+  expect(isControlled).toBe(true);
+});
+```
+
+### Offline Mode Testing
+
+**Use when**: Your PWA should work offline -- serving cached pages, showing offline indicators, queuing data for sync.
+**Avoid when**: Your app has no offline support.
+
+**TypeScript**
+```typescript
+import { test, expect } from '@playwright/test';
+
+test('app serves cached page when offline', async ({ swContext }) => {
+  const page = await swContext.newPage();
+
+  // First visit — caches the page and assets
+  await page.goto('/');
+  await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
+
+  // Wait for the service worker to finish caching
+  await page.evaluate(async () => {
+    const registration = await navigator.serviceWorker.ready;
+    // Wait for the SW to be in the 'activated' state
+    return registration.active?.state === 'activated';
+  });
+
+  // Go offline
+  await swContext.setOffline(true);
+
+  // Reload — should serve from cache
+  await page.reload();
+  await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
+
+  // Verify offline indicator appears
+  await expect(page.getByText('You are offline')).toBeVisible();
+
+  // Come back online
+  await swContext.setOffline(false);
+  await expect(page.getByText('You are offline')).toBeHidden();
+});
+
+test('form submission queues when offline', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/feedback');
+
+  // Ensure SW is active
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  // Go offline
+  await swContext.setOffline(true);
+
+  // Submit a form while offline
+  await page.getByLabel('Feedback').fill('Great product!');
+  await page.getByRole('button', { name: 'Submit' }).click();
+
+  // App should show a "queued" message, not an error
+  await expect(page.getByText('Saved offline. Will sync when connected.')).toBeVisible();
+
+  // Come back online — the queued data should sync
+  await swContext.setOffline(false);
+  await expect(page.getByText('Feedback submitted successfully')).toBeVisible({ timeout: 10000 });
+});
+```
+
+**JavaScript**
+```javascript
+const { test, expect } = require('@playwright/test');
+
+test('app serves cached page when offline', async ({ swContext }) => {
+  const page = await swContext.newPage();
+
+  await page.goto('/');
+  await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
+
+  await page.evaluate(async () => {
+    const registration = await navigator.serviceWorker.ready;
+    return registration.active?.state === 'activated';
+  });
+
+  await swContext.setOffline(true);
+  await page.reload();
+  await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();
+  await expect(page.getByText('You are offline')).toBeVisible();
+
+  await swContext.setOffline(false);
+  await expect(page.getByText('You are offline')).toBeHidden();
+});
+```
+
+### Cache Verification
+
+**Use when**: You need to confirm that specific resources are cached by the service worker.
+**Avoid when**: You trust the framework's caching strategy and only need to verify the offline UX (test offline mode instead).
+
+**TypeScript**
+```typescript
+import { test, expect } from '@playwright/test';
+
+test('critical assets are cached by the service worker', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+
+  // Wait for SW to be ready
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  // Check the cache contents
+  const cachedUrls = await page.evaluate(async () => {
+    const cacheNames = await caches.keys();
+    const allUrls: string[] = [];
+    for (const name of cacheNames) {
+      const cache = await caches.open(name);
+      const keys = await cache.keys();
+      allUrls.push(...keys.map((req) => new URL(req.url).pathname));
+    }
+    return allUrls;
+  });
+
+  // Verify critical resources are cached
+  expect(cachedUrls).toContain('/');
+  expect(cachedUrls).toContain('/offline.html');
+  expect(cachedUrls.some((url) => url.endsWith('.js'))).toBe(true);
+  expect(cachedUrls.some((url) => url.endsWith('.css'))).toBe(true);
+});
+
+test('cache is invalidated after service worker update', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+
+  // Get initial cache version
+  const initialCaches = await page.evaluate(() => caches.keys());
+
+  // Simulate a new SW version by clearing and reloading
+  await page.evaluate(async () => {
+    const registration = await navigator.serviceWorker.getRegistration();
+    await registration?.update();
+  });
+
+  // After update, old caches should be cleaned up
+  await page.reload();
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  const updatedCaches = await page.evaluate(() => caches.keys());
+
+  // The app should manage cache names with versioning
+  expect(updatedCaches.length).toBeGreaterThanOrEqual(1);
+});
+```
+
+**JavaScript**
+```javascript
+const { test, expect } = require('@playwright/test');
+
+test('critical assets are cached by the service worker', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  const cachedUrls = await page.evaluate(async () => {
+    const cacheNames = await caches.keys();
+    const allUrls = [];
+    for (const name of cacheNames) {
+      const cache = await caches.open(name);
+      const keys = await cache.keys();
+      allUrls.push(...keys.map((req) => new URL(req.url).pathname));
+    }
+    return allUrls;
+  });
+
+  expect(cachedUrls).toContain('/');
+  expect(cachedUrls).toContain('/offline.html');
+});
+```
+
+### PWA Install Prompt
+
+**Use when**: You need to test the "Add to Home Screen" / PWA install flow.
+**Avoid when**: Your app is not a PWA or does not handle the `beforeinstallprompt` event.
+
+The `beforeinstallprompt` event cannot be synthetically triggered by Playwright. Instead, verify that your app captures and handles the event correctly.
+
+**TypeScript**
+```typescript
+import { test, expect } from '@playwright/test';
+
+test('app captures install prompt and shows install button', async ({ swContext }) => {
+  const page = await swContext.newPage();
+
+  // Mock the beforeinstallprompt event
+  await page.addInitScript(() => {
+    let deferredPrompt: Event | null = null;
+
+    // Simulate the browser firing beforeinstallprompt
+    window.addEventListener('load', () => {
+      const event = new Event('beforeinstallprompt');
+      (event as any).preventDefault = () => {};
+      (event as any).prompt = () => Promise.resolve();
+      (event as any).userChoice = Promise.resolve({ outcome: 'accepted' });
+
+      window.dispatchEvent(event);
+    });
+  });
+
+  await page.goto('/');
+
+  // Your app should show an install button when it captures the prompt
+  await expect(page.getByRole('button', { name: 'Install app' })).toBeVisible();
+});
+
+test('web app manifest is valid', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+
+  // Verify manifest link exists
+  const manifestUrl = await page.evaluate(() => {
+    const link = document.querySelector('link[rel="manifest"]') as HTMLLinkElement;
+    return link?.href;
+  });
+  expect(manifestUrl).toBeTruthy();
+
+  // Fetch and validate the manifest
+  const response = await page.request.get(manifestUrl!);
+  expect(response.ok()).toBe(true);
+
+  const manifest = await response.json();
+  expect(manifest.name).toBeTruthy();
+  expect(manifest.icons).toHaveLength(expect.any(Number));
+  expect(manifest.start_url).toBeTruthy();
+  expect(manifest.display).toBe('standalone');
+});
+```
+
+**JavaScript**
+```javascript
+const { test, expect } = require('@playwright/test');
+
+test('app captures install prompt and shows install button', async ({ swContext }) => {
+  const page = await swContext.newPage();
+
+  await page.addInitScript(() => {
+    window.addEventListener('load', () => {
+      const event = new Event('beforeinstallprompt');
+      event.preventDefault = () => {};
+      event.prompt = () => Promise.resolve();
+      event.userChoice = Promise.resolve({ outcome: 'accepted' });
+      window.dispatchEvent(event);
+    });
+  });
+
+  await page.goto('/');
+  await expect(page.getByRole('button', { name: 'Install app' })).toBeVisible();
+});
+```
+
+### Push Notification Testing
+
+**Use when**: Your PWA uses the Push API to receive push notifications from a server.
+**Avoid when**: Notifications are handled entirely client-side without the Push API.
+
+**TypeScript**
+```typescript
+import { test, expect } from '@playwright/test';
+
+test('push notification triggers UI update', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+
+  // Wait for SW to be ready
+  const swURL = await page.evaluate(async () => {
+    const reg = await navigator.serviceWorker.ready;
+    return reg.active?.scriptURL;
+  });
+  expect(swURL).toBeTruthy();
+
+  // Get the service worker and evaluate inside it
+  const sw = swContext.serviceWorkers()[0];
+
+  // Simulate a push event inside the service worker
+  await sw.evaluate(async () => {
+    const event = new PushEvent('push', {
+      data: new TextEncoder().encode(JSON.stringify({
+        title: 'New Message',
+        body: 'You have a new message from Alice',
+        url: '/messages',
+      })),
+    });
+    // @ts-ignore — dispatchEvent works in SW context
+    self.dispatchEvent(event);
+  });
+
+  // Verify the app reacts (e.g., shows a badge or notification banner)
+  await expect(page.getByTestId('notification-badge')).toHaveText('1');
+});
+```
+
+**JavaScript**
+```javascript
+const { test, expect } = require('@playwright/test');
+
+test('push notification triggers UI update', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/');
+
+  const swURL = await page.evaluate(async () => {
+    const reg = await navigator.serviceWorker.ready;
+    return reg.active?.scriptURL;
+  });
+  expect(swURL).toBeTruthy();
+
+  const sw = swContext.serviceWorkers()[0];
+
+  await sw.evaluate(async () => {
+    const event = new PushEvent('push', {
+      data: new TextEncoder().encode(JSON.stringify({
+        title: 'New Message',
+        body: 'You have a new message from Alice',
+        url: '/messages',
+      })),
+    });
+    self.dispatchEvent(event);
+  });
+
+  await expect(page.getByTestId('notification-badge')).toHaveText('1');
+});
+```
+
+### Background Sync Testing
+
+**Use when**: Your app uses the Background Sync API to defer network requests until the user has connectivity.
+**Avoid when**: Your app does not use background sync.
+
+**TypeScript**
+```typescript
+import { test, expect } from '@playwright/test';
+
+test('background sync retries failed requests when online', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/tasks');
+
+  // Ensure SW is active
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  // Go offline
+  await swContext.setOffline(true);
+
+  // Create a task (will fail to sync)
+  await page.getByLabel('New task').fill('Buy groceries');
+  await page.getByRole('button', { name: 'Add' }).click();
+
+  // Task shows as "pending sync"
+  await expect(page.getByText('Buy groceries')).toBeVisible();
+  await expect(page.getByTestId('sync-status')).toHaveText('Pending');
+
+  // Come back online — background sync should fire
+  await swContext.setOffline(false);
+
+  // Wait for sync to complete
+  await expect(page.getByTestId('sync-status')).toHaveText('Synced', { timeout: 15000 });
+});
+```
+
+**JavaScript**
+```javascript
+const { test, expect } = require('@playwright/test');
+
+test('background sync retries failed requests when online', async ({ swContext }) => {
+  const page = await swContext.newPage();
+  await page.goto('/tasks');
+  await page.evaluate(() => navigator.serviceWorker.ready);
+
+  await swContext.setOffline(true);
+
+  await page.getByLabel('New task').fill('Buy groceries');
+  await page.getByRole('button', { name: 'Add' }).click();
+
+  await expect(page.getByText('Buy groceries')).toBeVisible();
+  await expect(page.getByTestId('sync-status')).toHaveText('Pending');
+
+  await swContext.setOffline(false);
+  await expect(page.getByTestId('sync-status')).toHaveText('Synced', { timeout: 15000 });
+});
+```
+
+## Decision Guide
+
+| Scenario | Approach | Why |
+|---|---|---|
+| Verify SW registers | `context.waitForEvent('serviceworker')` | Confirms the SW file was fetched and registered |
+| Test offline page serving | `context.setOffline(true)` + reload | Simulates network loss at the browser level |
+| Verify specific assets are cached | `page.evaluate(() => caches.keys())` | Directly queries the Cache API |
+| Test install prompt | `addInitScript` to mock `beforeinstallprompt` | Browser does not fire this event in automation |
+| Validate web manifest | `page.request.get(manifestUrl)` | Fetch and parse the JSON manifest |
+| Test push notifications | `sw.evaluate()` to dispatch PushEvent | Simulates a push message inside the SW |
+| Test background sync | Go offline, perform action, come back online | Verifies the sync queue processes correctly |
+| Test SW update flow | `registration.update()` via `page.evaluate` | Triggers a manual SW update check |
+
+## Anti-Patterns
+
+| Don't Do This | Problem | Do This Instead |
+|---|---|---|
+| Test service workers with the default `page` fixture | Default context is temporary; SWs may not persist | Use `launchPersistentContext` for reliable SW testing |
+| Skip `navigator.serviceWorker.ready` before going offline | SW may not have finished caching | Always `await page.evaluate(() => navigator.serviceWorker.ready)` first |
+| Use `page.route()` to simulate offline | Only intercepts Playwright-visible requests; SW fetch events are not intercepted | Use `context.setOffline(true)` for true network-level offline |
+| Test the SW JavaScript file directly with unit tests only | Misses integration with the page and caching behavior | Combine unit tests with Playwright end-to-end SW tests |
+| Assume caches are clean at test start | Previous test runs may leave stale caches | Clear caches in fixture setup or use a fresh `userDataDir` |
+| `waitForTimeout` after `setOffline(false)` | Background sync timing is unpredictable | Use `expect(...).toHaveText('Synced', { timeout: 15000 })` |
+
+## Troubleshooting
+
+| Symptom | Cause | Fix |
+|---|---|---|
+| `context.waitForEvent('serviceworker')` never resolves | SW already registered before listener attached | Register listener before `page.goto()`, or check `context.serviceWorkers()` |
+| SW does not activate | Old SW is still controlling the page | Use `skipWaiting()` in the SW or clear the `userDataDir` |
+| Offline test still loads fresh content | SW cache was not populated before going offline | Wait for `navigator.serviceWorker.ready` and verify cache contents first |
+| `context.setOffline(true)` has no effect | Using a non-persistent context or the wrong context | Ensure offline is set on the same context that owns the page |
+| Push event does nothing | SW is not the active controller | Ensure `sw.evaluate()` targets the correct service worker from `context.serviceWorkers()` |
+| Tests interfere with each other | Shared `userDataDir` between tests | Use a unique temp directory per test, cleaned in fixture teardown |
+| Service worker tests only work in Chromium | Firefox and WebKit have limited SW support in Playwright | Run SW tests in Chromium only via `test.skip` or project config |
+
+## Related
+
+- [core/browser-apis.md](browser-apis.md) -- IndexedDB and localStorage used alongside service workers
+- [core/configuration.md](configuration.md) -- project-level config for PWA testing
+- [core/fixtures-and-hooks.md](fixtures-and-hooks.md) -- wrapping persistent context in fixtures
+- [core/websockets-and-realtime.md](websockets-and-realtime.md) -- real-time features that interact with offline/online state