rust_browser/_bmad/tea/testarch/knowledge/overview.md

Playwright Utils Overview

Principle

Use production-ready, fixture-based utilities from @seontechnologies/playwright-utils for common Playwright testing patterns. Build test helpers as pure functions first, then wrap in framework-specific fixtures for composability and reuse. Works equally well for pure API testing (no browser) and UI testing.

Rationale

Writing Playwright utilities from scratch for every project leads to:

• Duplicated code across test suites
• Inconsistent patterns and quality
• Maintenance burden when Playwright APIs change
• Missing advanced features (schema validation, HAR recording, auth persistence)

@seontechnologies/playwright-utils provides:

• Production-tested utilities: Used at SEON Technologies in production
• Functional-first design: Core logic as pure functions, fixtures for convenience
• Composable fixtures: Use mergeTests to combine utilities
• TypeScript support: Full type safety with generic types
• Comprehensive coverage: API requests, auth, network, logging, file handling, burn-in
• Backend-first mentality: Most utilities work without a browser - pure API/service testing is a first-class use case

Installation

npm install -D @seontechnologies/playwright-utils

Peer Dependencies:

• @playwright/test >= 1.54.1 (required)
• ajv >= 8.0.0 (optional - for JSON Schema validation)
• zod >= 3.0.0 (optional - for Zod schema validation)

Available Utilities

Core Testing Utilities

Utility	Purpose	Test Context
api-request	Typed HTTP client with schema validation, retry, and operation-based overload	API/Backend
recurse	Polling for async operations, background jobs	API/Backend
auth-session	Token persistence, multi-user, service-to-service	API/Backend/UI
log	Playwright report-integrated logging	API/Backend/UI
file-utils	CSV/XLSX/PDF/ZIP reading & validation	API/Backend/UI
burn-in	Smart test selection with git diff	CI/CD
network-recorder	HAR record/playback for offline testing	UI only
intercept-network-call	Network spy/stub with auto JSON parsing	UI only
network-error-monitor	Automatic HTTP 4xx/5xx detection	UI only

Note: 6 of 9 utilities work without a browser. Only 3 are UI-specific (network-recorder, intercept-network-call, network-error-monitor).

Design Patterns

Pattern 1: Functional Core, Fixture Shell

Context: All utilities follow the same architectural pattern - pure function as core, fixture as wrapper.

Implementation:

// Direct import (pass Playwright context explicitly)
import { apiRequest } from '@seontechnologies/playwright-utils';

test('direct usage', async ({ request }) => {
  const { status, body } = await apiRequest({
    request, // Must pass request context
    method: 'GET',
    path: '/api/users',
  });
});

// Fixture import (context injected automatically)
import { test } from '@seontechnologies/playwright-utils/fixtures';

test('fixture usage', async ({ apiRequest }) => {
  const { status, body } = await apiRequest({
    // No need to pass request context
    method: 'GET',
    path: '/api/users',
  });
});

Key Points:

• Pure functions testable without Playwright running
• Fixtures inject framework dependencies automatically
• Choose direct import (more control) or fixture (convenience)

Pattern 2: Subpath Imports for Tree-Shaking

Context: Import only what you need to keep bundle sizes small.

Implementation:

// Import specific utility
import { apiRequest } from '@seontechnologies/playwright-utils/api-request';

// Import specific fixture
import { test } from '@seontechnologies/playwright-utils/api-request/fixtures';

// Import everything (use sparingly)
import { apiRequest, recurse, log } from '@seontechnologies/playwright-utils';

Key Points:

• Subpath imports enable tree-shaking
• Keep bundle sizes minimal
• Import from specific paths for production builds

Pattern 3: Fixture Composition with mergeTests

Context: Combine multiple playwright-utils fixtures with your own custom fixtures.

Implementation:

// playwright/support/merged-fixtures.ts
import { mergeTests } from '@playwright/test';
import { test as apiRequestFixture } from '@seontechnologies/playwright-utils/api-request/fixtures';
import { test as authFixture } from '@seontechnologies/playwright-utils/auth-session/fixtures';
import { test as recurseFixture } from '@seontechnologies/playwright-utils/recurse/fixtures';
import { test as logFixture } from '@seontechnologies/playwright-utils/log/fixtures';

// Merge all fixtures into one test object
export const test = mergeTests(apiRequestFixture, authFixture, recurseFixture, logFixture);

export { expect } from '@playwright/test';

// In your tests
import { test, expect } from '../support/merged-fixtures';

test('all utilities available', async ({ apiRequest, authToken, recurse, log }) => {
  await log.step('Making authenticated API request');

  const { body } = await apiRequest({
    method: 'GET',
    path: '/api/protected',
    headers: { Authorization: `Bearer ${authToken}` },
  });

  await recurse(
    () => apiRequest({ method: 'GET', path: `/status/${body.id}` }),
    (res) => res.body.ready === true,
  );
});

Key Points:

• mergeTests combines multiple fixtures without conflicts
• Create one merged-fixtures.ts file per project
• Import test object from your merged fixtures in all tests
• All utilities available in single test signature

Integration with Existing Tests

Gradual Adoption Strategy

1. Start with logging (zero breaking changes):

import { log } from '@seontechnologies/playwright-utils';

test('existing test', async ({ page }) => {
  await log.step('Navigate to page'); // Just add logging
  await page.goto('/dashboard');
  // Rest of test unchanged
});

2. Add API utilities (for API tests):

import { test } from '@seontechnologies/playwright-utils/api-request/fixtures';

test('API test', async ({ apiRequest }) => {
  const { status, body } = await apiRequest({
    method: 'GET',
    path: '/api/users',
  });

  expect(status).toBe(200);
});

3. Expand to network utilities (for UI tests):

import { test } from '@seontechnologies/playwright-utils/fixtures';

test('UI with network control', async ({ page, interceptNetworkCall }) => {
  const usersCall = interceptNetworkCall({
    url: '**/api/users',
  });

  await page.goto('/dashboard');
  const { responseJson } = await usersCall;

  expect(responseJson).toHaveLength(10);
});

4. Full integration (merged fixtures):

Create merged-fixtures.ts and use across all tests.

Related Fragments

• api-request.md - HTTP client with schema validation
• network-recorder.md - HAR-based offline testing
• auth-session.md - Token management
• intercept-network-call.md - Network interception
• recurse.md - Polling patterns
• log.md - Logging utility
• file-utils.md - File operations
• fixtures-composition.md - Advanced mergeTests patterns

Anti-Patterns

❌ Don't mix direct and fixture imports in same test:

import { apiRequest } from '@seontechnologies/playwright-utils';
import { test } from '@seontechnologies/playwright-utils/auth-session/fixtures';

test('bad', async ({ request, authToken }) => {
  // Confusing - mixing direct (needs request) and fixture (has authToken)
  await apiRequest({ request, method: 'GET', path: '/api/users' });
});

✅ Use consistent import style:

import { test } from '../support/merged-fixtures';

test('good', async ({ apiRequest, authToken }) => {
  // Clean - all from fixtures
  await apiRequest({ method: 'GET', path: '/api/users' });
});

❌ Don't import everything when you need one utility:

import * as utils from '@seontechnologies/playwright-utils'; // Large bundle

✅ Use subpath imports:

import { apiRequest } from '@seontechnologies/playwright-utils/api-request'; // Small bundle

Reference Implementation

The official @seontechnologies/playwright-utils repository provides working examples of all patterns described in these fragments.

Repository: https://github.com/seontechnologies/playwright-utils

Key resources:

• Test examples: playwright/tests - All utilities in action
• Framework setup: playwright.config.ts, playwright/support/merged-fixtures.ts
• CI patterns: .github/workflows/ - GitHub Actions with sharding, parallelization

Quick start:

git clone https://github.com/seontechnologies/playwright-utils.git
cd playwright-utils
nvm use
npm install
npm run test:pw-ui  # Explore tests with Playwright UI
npm run test:pw

All patterns in TEA fragments are production-tested in this repository.