QA Testing (Playwright)

High-signal, cost-aware E2E testing for web applications.

Core docs:

Defaults (2026)

Keep E2E thin: protect critical user journeys only; push coverage down (unit/integration/contract).
Locator priority: getByRole → getByLabel/getByText → getByTestId (fallback).
Waiting: rely on Playwright auto-wait + web-first assertions; no sleeps/time-based waits.
Isolation: tests must run alone, in parallel, and in any order; eliminate shared mutable state.
Flake posture: retries are a debugging tool; treat rerun-pass as a failure signal and fix root cause.
CI posture: smoke gate on PRs; shard/parallelize regression on schedule; always keep artifacts (trace/video/screenshot).

Quick Start

Command	Purpose
`npm init playwright@latest`	Initialize Playwright
`npx playwright test`	Run all tests
`npx playwright test --grep @smoke`	Run smoke tests
`npx playwright test --project=chromium`	Run a single project
`npx playwright test --ui`	Debug with UI mode
`npx playwright test --debug`	Step through a test
`npx playwright show-trace trace.zip`	Inspect trace artifacts
`npx playwright show-report`	Inspect HTML report

When to Use

E2E tests for web applications
Test user authentication flows
Verify form submissions
Test responsive designs
Automate browser interactions
Set up Playwright in CI/CD

When NOT to Use

Scenario	Use Instead
Unit testing	Jest, Vitest, pytest
API contracts	qa-api-testing-contracts
Load testing	k6, Locust, Artillery
Mobile native	Appium

Authoring Rules

Locator Strategy

// 1. Role locators (preferred)
await page.getByRole('button', { name: 'Sign in' }).click();

// 2. Label/text locators
await page.getByLabel('Email').fill('user@example.com');

// 3. Test IDs (fallback)
await page.getByTestId('user-avatar').click();

Flake Control

Avoid sleeps; use Playwright auto-wait
Use retries as signal, not a crutch
Capture trace/screenshot/video on failure
Prefer user-like interactions; avoid force: true

Workflow

Write the smallest test that proves the user outcome (intent + oracle).
Stabilize locators and assertions before adding more steps.
Make state explicit: seed per test/worker, clean up deterministically, mock third-party boundaries.
In CI: shard/parallelize, capture artifacts, and fail fast on rerun-pass flakes.

Debugging Checklist

If something is flaky:

Open trace first; identify whether it is selector ambiguity, missing wait, or state leakage.
Replace brittle selectors with semantic locators; replace sleeps with expect(...) or a targeted wait.
Reduce global timeouts; add scoped timeouts only when the product truly needs it.
If it only fails in CI, look for concurrency, cold-start, CPU starvation, and environment differences.

Do / Avoid

Make tests independent and deterministic
Use network mocking for third-party deps
Run smoke E2E on PRs; full regression on schedule
"Test everything E2E" as default
Weakening assertions to "fix" flakes
Auto-healing that weakens assertions

Execution Preflight (High ROI)

Run this preflight before expensive E2E runs to prevent avoidable failures.

Preflight Checklist

Repository shape:

Confirm working directory and expected app root exist.
Verify spec paths before execution (rg --files tests/e2e | rg <target>).

Port/process hygiene:

Check and clear stale dev server port before run (example: lsof -i :3001).
Avoid parallel local servers colliding with Playwright webServer.

Command validity:

Validate CLI flags for current tool versions before batch runs.
Prefer exact spec paths or --grep over broad globs during triage.

Artifact expectations:

Confirm result artifact paths exist before reading (test -f <error-context.md>).
If artifact path missing, inspect latest test-results index first.

Mandatory Sandbox/Port Decisions

Before running Playwright in constrained environments (sandboxed terminals, CI containers, shared dev hosts), decide and document:

Bind host/port: confirm whether app server must use 127.0.0.1 or 0.0.0.0, and verify selected port is free.
Escalation path: if bind attempts fail with EPERM/EACCES, escalate immediately instead of retry loops.
Long-flow timeout budget: set explicit per-test timeout for API-heavy flows (generation/checkout/report) instead of inflating global timeout.
Build lock hygiene: clear stale .next/lock and terminate stale build/dev PIDs before rerun.

Triage Sequence (Fastest Signal)

Reproduce one failing test with --workers=1.
Capture trace/video/screenshot for that single failure.
Fix determinism root cause.
Re-run targeted suite.
Only then run broad regression.

Failure Patterns to Treat as Environment, Not Product Bugs

EADDRINUSE on Playwright web server port
Missing spec/result paths from stale assumptions
Shell glob expansion failures for bracketed route segments

Resources

Resource	Purpose
references/playwright-mcp.md	MCP & AI testing
references/playwright-patterns.md	Advanced patterns
references/playwright-ci.md	CI configurations
references/playwright-authentication.md	Auth patterns and session management
references/visual-regression-testing.md	Visual regression strategies
references/api-testing-playwright.md	API testing with APIRequestContext
references/playwright-preflight-sandbox.md	Sandbox/port preflight and escalation decisions
data/sources.json	Documentation links

Templates

Template	Purpose
assets/template-playwright-e2e-review-checklist.md	E2E review checklist
assets/template-playwright-fail-on-flaky-reporter.js	Fail CI on rerun-pass flakes
assets/template-playwright-preflight-checklist.md	Preflight checklist for port/sandbox/timeouts

Related Skills

Skill	Purpose
qa-testing-strategy	Overall test strategy
software-frontend	Frontend development
ops-devops-platform	CI/CD integration

Fact-Checking

Use web search/web fetch to verify current external facts, versions, pricing, deadlines, regulations, or platform behavior before final answers.
Prefer primary sources; report source links and dates for volatile information.
If web access is unavailable, state the limitation and mark guidance as unverified.

qa-testing-playwright