ECC/skills/e2e-testing/SKILL.md

name, description, metadata

name	description	metadata
e2e-testing	Playwright E2E testing patterns, Page Object Model, configuration, CI/CD integration, artifact management, and flaky test strategies. Use when writing Playwright tests, structuring page objects, or fixing flaky E2E runs in CI.	origin ECC

E2E Testing Patterns

Comprehensive Playwright patterns for building stable, fast, and maintainable E2E test suites.

Test File Organization

tests/
├── e2e/
│   ├── auth/
│   │   ├── login.spec.ts
│   │   ├── logout.spec.ts
│   │   └── register.spec.ts
│   ├── features/
│   │   ├── browse.spec.ts
│   │   ├── search.spec.ts
│   │   └── create.spec.ts
│   └── api/
│       └── endpoints.spec.ts
├── fixtures/
│   ├── auth.ts
│   └── data.ts
└── playwright.config.ts

Page Object Model (POM)

import { Page, Locator } from '@playwright/test'

export class ItemsPage {
  readonly page: Page
  readonly searchInput: Locator
  readonly itemCards: Locator
  readonly createButton: Locator

  constructor(page: Page) {
    this.page = page
    this.searchInput = page.locator('[data-testid="search-input"]')
    this.itemCards = page.locator('[data-testid="item-card"]')
    this.createButton = page.locator('[data-testid="create-btn"]')
  }

  async goto() {
    await this.page.goto('/items')
    await this.page.waitForLoadState('networkidle')
  }

  async search(query: string) {
    await this.searchInput.fill(query)
    await this.page.waitForResponse(resp => resp.url().includes('/api/search'))
    await this.page.waitForLoadState('networkidle')
  }

  async getItemCount() {
    return await this.itemCards.count()
  }
}

Test Structure

import { test, expect } from '@playwright/test'
import { ItemsPage } from '../../pages/ItemsPage'

test.describe('Item Search', () => {
  let itemsPage: ItemsPage

  test.beforeEach(async ({ page }) => {
    itemsPage = new ItemsPage(page)
    await itemsPage.goto()
  })

  test('should search by keyword', async ({ page }) => {
    await itemsPage.search('test')

    const count = await itemsPage.getItemCount()
    expect(count).toBeGreaterThan(0)

    await expect(itemsPage.itemCards.first()).toContainText(/test/i)
    await page.screenshot({ path: 'artifacts/search-results.png' })
  })

  test('should handle no results', async ({ page }) => {
    await itemsPage.search('xyznonexistent123')

    await expect(page.locator('[data-testid="no-results"]')).toBeVisible()
    expect(await itemsPage.getItemCount()).toBe(0)
  })
})

Playwright Configuration

import { defineConfig, devices } from '@playwright/test'

export default defineConfig({
  testDir: './tests/e2e',
  fullyParallel: true,
  forbidOnly: !!process.env.CI,
  retries: process.env.CI ? 2 : 0,
  workers: process.env.CI ? 1 : undefined,
  reporter: [
    ['html', { outputFolder: 'playwright-report' }],
    ['junit', { outputFile: 'playwright-results.xml' }],
    ['json', { outputFile: 'playwright-results.json' }]
  ],
  use: {
    baseURL: process.env.BASE_URL || 'http://localhost:3000',
    trace: 'on-first-retry',
    screenshot: 'only-on-failure',
    video: 'retain-on-failure',
    actionTimeout: 10000,
    navigationTimeout: 30000,
  },
  projects: [
    { name: 'chromium', use: { ...devices['Desktop Chrome'] } },
    { name: 'firefox', use: { ...devices['Desktop Firefox'] } },
    { name: 'webkit', use: { ...devices['Desktop Safari'] } },
    { name: 'mobile-chrome', use: { ...devices['Pixel 5'] } },
  ],
  webServer: {
    command: 'npm run dev',
    url: 'http://localhost:3000',
    reuseExistingServer: !process.env.CI,
    timeout: 120000,
  },
})

Flaky Test Patterns

Quarantine

test('flaky: complex search', async ({ page }) => {
  test.fixme(true, 'Flaky - Issue #123')
  // test code...
})

test('conditional skip', async ({ page }) => {
  test.skip(process.env.CI, 'Flaky in CI - Issue #123')
  // test code...
})

Identify Flakiness

npx playwright test tests/search.spec.ts --repeat-each=10
npx playwright test tests/search.spec.ts --retries=3

Common Causes & Fixes

Race conditions:

// Bad: assumes element is ready
await page.click('[data-testid="button"]')

// Good: auto-wait locator
await page.locator('[data-testid="button"]').click()

Network timing:

// Bad: arbitrary timeout
await page.waitForTimeout(5000)

// Good: wait for specific condition
await page.waitForResponse(resp => resp.url().includes('/api/data'))

Animation timing:

// Bad: click during animation
await page.click('[data-testid="menu-item"]')

// Good: wait for stability
await page.locator('[data-testid="menu-item"]').waitFor({ state: 'visible' })
await page.waitForLoadState('networkidle')
await page.locator('[data-testid="menu-item"]').click()

Artifact Management

Screenshots

await page.screenshot({ path: 'artifacts/after-login.png' })
await page.screenshot({ path: 'artifacts/full-page.png', fullPage: true })
await page.locator('[data-testid="chart"]').screenshot({ path: 'artifacts/chart.png' })

Traces

await browser.startTracing(page, {
  path: 'artifacts/trace.json',
  screenshots: true,
  snapshots: true,
})
// ... test actions ...
await browser.stopTracing()

Video

// In playwright.config.ts
use: {
  video: 'retain-on-failure',
  videosPath: 'artifacts/videos/'
}

CI/CD Integration

# .github/workflows/e2e.yml
name: E2E Tests
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm ci
      - run: npx playwright install --with-deps
      - run: npx playwright test
        env:
          BASE_URL: ${{ vars.STAGING_URL }}
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: playwright-report
          path: playwright-report/
          retention-days: 30

Test Report Template

# E2E Test Report

**Date:** YYYY-MM-DD HH:MM
**Duration:** Xm Ys
**Status:** PASSING / FAILING

## Summary
- Total: X | Passed: Y (Z%) | Failed: A | Flaky: B | Skipped: C

## Failed Tests

### test-name
**File:** `tests/e2e/feature.spec.ts:45`
**Error:** Expected element to be visible
**Screenshot:** artifacts/failed.png
**Recommended Fix:** [description]

## Artifacts
- HTML Report: playwright-report/index.html
- Screenshots: artifacts/*.png
- Videos: artifacts/videos/*.webm
- Traces: artifacts/*.zip

Wallet / Web3 Testing

test('wallet connection', async ({ page, context }) => {
  // Mock wallet provider
  await context.addInitScript(() => {
    window.ethereum = {
      isMetaMask: true,
      request: async ({ method }) => {
        if (method === 'eth_requestAccounts')
          return ['0x1234567890123456789012345678901234567890']
        if (method === 'eth_chainId') return '0x1'
      }
    }
  })

  await page.goto('/')
  await page.locator('[data-testid="connect-wallet"]').click()
  await expect(page.locator('[data-testid="wallet-address"]')).toContainText('0x1234')
})

Financial / Critical Flow Testing

test('trade execution', async ({ page }) => {
  // Skip on production — real money
  test.skip(process.env.NODE_ENV === 'production', 'Skip on production')

  await page.goto('/markets/test-market')
  await page.locator('[data-testid="position-yes"]').click()
  await page.locator('[data-testid="trade-amount"]').fill('1.0')

  // Verify preview
  const preview = page.locator('[data-testid="trade-preview"]')
  await expect(preview).toContainText('1.0')

  // Confirm and wait for blockchain
  await page.locator('[data-testid="confirm-trade"]').click()
  await page.waitForResponse(
    resp => resp.url().includes('/api/trade') && resp.status() === 200,
    { timeout: 30000 }
  )

  await expect(page.locator('[data-testid="trade-success"]')).toBeVisible()
})