E2E Test Generator Skill

This skill generates E2E tests using playwright-cli commands for browser automation. It uses the Page Object Model pattern and supports visual regression testing with the @visual tag in test titles.

When to Use

Use this skill when:

• The user provides a URL to explore and create tests for
• You need to create new E2E tests for a web application
• You want to generate Page Object classes for a website
• Visual regression tests are needed (integrated with integration tests using @visual tag)

Prerequisites

• playwright-cli installed globally (npm install -g @playwright/cli@latest)
• Target URL must be accessible
• Project should have Playwright configured

Workflow Overview

1. EXPLORE → Navigate to URL, take snapshot, understand the page structure
2. PLAN → Identify testable features and create test plan
3. GENERATE PAGES → Create Page Object classes
4. GENERATE TESTS → Create test specs (add @visual tag for visual checks)
5. VALIDATE → Run tests to ensure they pass

References

For detailed exploration techniques and CLI commands, see:

• references/component-exploration.md – How to explore UI components, CLI browser commands, locator strategies
• references/api-mocking.md – How to mock API responses using mockApi utility for deterministic tests

Examples

For code templates and patterns, see:

• examples/page-object-model.md – Page Object class templates and helper patterns
• examples/e2e-tests.md – Integration test templates with @visual tag for visual testing

Quick Start Workflow

Phase 1: URL Exploration

1. Open URL

   playwright-cli open https://example.com
   

2. Take Page Snapshot

   playwright-cli snapshot
   

3. Identify Interactive Elements from snapshot output:

   • Buttons, links, form inputs
   • Navigation elements
   • Modal triggers
   • Dropdown menus

4. Test Interactions before generating code:

   playwright-cli click e12
   playwright-cli snapshot  # Verify result
   

Phase 2: Test Planning

Based on exploration, identify:

1. Happy Path Tests – Core user workflows
2. Edge Cases – Error states, boundary conditions
3. Visual Tests – UI consistency checks (add @visual tag to test title when needed)

Phase 3: Generate Page Objects

See examples/page-object-model.md for templates.

Key rules:

• All locators as readonly class properties
• Initialize locators in constructor
• Every interaction method has waitFor before action
• Use .catch(() => false) for visibility checks

Phase 4: Generate Tests

See examples/e2e-tests.md for templates.

Key patterns:

• Add @visual tag to test title for visual regression tests (e.g., 'should display page correctly @visual')
• Follow AAA pattern (Arrange, Act, Assert)
• Create constants for reusable test data
• All logic in Page Objects (no separate helpers or fixtures)

Test File Structure

__tests__/
├── e2e/
│   ├── pages/           # Page Object classes (ALL locators & interaction logic)
│   │   └── [page-name]-page.ts
│   └── [feature].spec.ts  # Integration tests (include @visual tag for visual checks)
└── constants/           # Test data only (URLs, emails, text values)
    └── test-data.ts

Important Notes:

• All locators in Page Objects – No separate selectors file, locators are defined as class properties
• No helpers folder – All interaction methods belong in Page Object classes
• No fixtures folder – Use standard Playwright test setup
• No visual folder – Visual tests are integrated with integration tests using @visual tag

Visual Testing Best Practices

ALWAYS Prefer Component-Level Screenshots

Never use full-page screenshots. Component-level screenshots are more stable and focused:

// CORRECT - Component-level screenshot
await expect(featurePage.header).toHaveScreenshot('preview-mode-header.png');
await expect(featurePage.globalStylesPanel).toHaveScreenshot('styles-expanded.png');

// WRONG - Full-page screenshot (too fragile)
await expect(page).toHaveScreenshot('preview-mode.png');

Why Component-Level Screenshots?

Strict Pixel Comparison

In playwright.config.ts, use strict comparison (no tolerance):

expect: {
  toHaveScreenshot: {
    maxDiffPixels: 0, // Strict - no pixel difference allowed
  },
},

Add Component Locators to Page Objects

// In your Page Object class constructor
this.header = page.locator('.guido__header, header').first();
this.globalStylesPanel = page.getByRole('tabpanel', { name: 'General Styles' });
this.leftSidebar = page.locator('.left-sidebar, [class*="sidebar"]').first();

Screenshot Naming Convention

Use descriptive names that indicate the component and state:

// Good names
await expect(featurePage.header).toHaveScreenshot('header-preview-mode.png');
await expect(featurePage.globalStylesPanel).toHaveScreenshot('styles-mobile-view.png');

// Bad names (too generic)
await expect(element).toHaveScreenshot('test1.png');

API Mocking

For deterministic tests, mock API responses using the mockApi utility:

import { API_ENDPOINTS } from '../enums/constants';
import { mockApi } from '../mockServer';

test('displays empty state @visual', async ({ page }) => {
  // Setup mocks BEFORE navigation
  await mockApi(page, `**/${API_ENDPOINTS.LIST_DATA}**`, 'list-data/empty.json');

  const featurePage = new FeaturePage(page);
  await featurePage.goto('/page');
  await expect(featurePage.emptyState).toHaveScreenshot('empty-state.png');
});

See references/api-mocking.md for full documentation.

Important Notes

• Always explore first – Use playwright-cli snapshot before writing any code
• Mock APIs – Use mockApi utility for deterministic test data
• Test interactions – Verify element refs work before generating Page Objects
• Visual tests use @visual tag in title – e.g., 'component visual test @visual'
• Use component-level screenshots – NEVER use full-page screenshots
• Strict pixel comparison – Use maxDiffPixels: 0 in config
• Don’t separate visual tests – Integrate them with integration tests when needed
• Follow existing patterns – Match project structure exactly
• Use descriptive names – Test names should describe expected behavior
• Keep Page Objects comprehensive – Include wait methods, helper methods, and assertion helpers
• Never use page.waitForTimeout() – Use proper waitFor conditions instead

Error Handling

GitHub Actions Workflow

Example CI/CD workflow for E2E tests with sharding and visual regression:

name: E2E Tests

on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]
  push:
    branches: [develop]
  workflow_dispatch:
    inputs:
      update_snapshots:
        description: 'Update snapshots only'
        required: false
        default: 'false'
        type: boolean

jobs:
  run-e2e-tests:
    if: github.event_name == 'workflow_dispatch' || github.event_name == 'pull_request' || github.event_name == 'push'
    timeout-minutes: 60
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        shardIndex: [1, 2, 3, 4]
        shardTotal: [4]
    permissions:
      contents: read
      issues: write
      pull-requests: write
    env:
      APP_URL: https://localhost:3000
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm

      - name: Install dependencies
        run: npm ci

      - name: Install Playwright browsers
        run: npx playwright install --with-deps

      - name: Start dev server
        run: |
          npm run dev &
          npx wait-on ${{ env.APP_URL }}

      - name: Run E2E Tests
        run: |
          if [ "${{ inputs.update_snapshots }}" == "true" ]; then
            npx playwright test --grep @visual --update-snapshots --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --reporter=blob
          else
            npx playwright test --shard=${{ matrix.shardIndex }}/${{ matrix.shardTotal }} --reporter=blob
          fi

      - name: Upload blob report
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: blob-report-${{ github.run_id }}-${{ matrix.shardIndex }}
          path: blob-report/
          retention-days: 3

  merge-reports:
    if: always()
    needs: [run-e2e-tests]
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm

      - name: Install dependencies
        run: npm ci

      - name: Download blob reports
        uses: actions/download-artifact@v4
        with:
          path: all-blob-reports
          pattern: blob-report-${{ github.run_id }}-*
          merge-multiple: true

      - name: Merge reports
        run: npx playwright merge-reports --reporter html ./all-blob-reports

      - name: Upload HTML report
        uses: actions/upload-artifact@v4
        with:
          name: playwright-report
          path: playwright-report/
          retention-days: 7

Key Workflow Features