A11y Playwright Testing Agent Skill

Playwright Accessibility Testing (TypeScript)

Comprehensive toolkit for automated accessibility testing using Playwright with TypeScript and axe-core. Enables WCAG 2.2 Level AA compliance verification (superset of 2.1), keyboard operability testing, semantic validation, and accessibility regression prevention.

> Activation: This skill is triggered when working with accessibility testing, WCAG compliance, axe-core scans, keyboard navigation tests, focus management, ARIA validation, or screen reader compatibility.

When to Use This Skill

• Automated a11y scans with axe-core for WCAG 2.2 AA compliance
• Keyboard navigation tests for Tab/Enter/Space/Escape/Arrow key operability
• Focus management validation for dialogs, menus, and dynamic content
• Semantic structure assertions for landmarks, headings, and ARIA
• Form accessibility testing for labels, errors, and instructions
• Color contrast and visual accessibility verification
• Screen reader compatibility testing patterns

Do NOT Use For

• Selenium/Java accessibility testing (use accessibility-selenium-testing).
• Authoring Playwright functional/UI E2E specs (use playwright-e2e-testing).
• Full conformance sign-off — automated axe scans catch ~30-40% of issues; manual audit + assistive-tech testing is still required.

Prerequisites

| Requirement | Details |

| ----------- | ------------------------------ |

| Node.js | v18+ recommended |

| Playwright | @playwright/test installed |

| axe-core | @axe-core/playwright package |

| TypeScript | Configured in project |

Quick Setup

# Add axe-core to existing Playwright project
npm install -D @axe-core/playwright axe-core

First Questions to Ask

Before writing accessibility tests, clarify:

• Scope: Which pages/flows are in scope? What's explicitly excluded?
• Standard: WCAG 2.2 AA (default) or specific organizational policy?
• Priority: Which components are highest risk (forms, modals, navigation, checkout)?
• Exceptions: Known constraints (legacy markup, third-party widgets)?
• Assistive Tech: Which screen readers/browsers need manual testing?

Core Principles

1. Automation Limitations

> [!] Critical: Automated tooling can detect ~30-40% of accessibility issues. Use automation to prevent regressions and catch common failures; manual audits are required for full WCAG conformance.

2. Semantic HTML First

Prefer native HTML semantics over ARIA. Use ARIA only when native elements cannot achieve the required semantics.

// [ok] Semantic HTML - inherently accessible
await page.getByRole("button", { name: "Submit" }).click();

// [no] ARIA override - requires manual keyboard/focus handling
await page.locator('[role="button"]').click(); // Often a <div>

3. Locator Strategy as A11y Signal

If you cannot locate an element by role or label, it's often an accessibility defect.

| Locator Success | Accessibility Signal |

| -------------------------------------------- | -------------------------- |

| getByRole('button', { name: 'Submit' }) [ok] | Button has accessible name |

| getByLabel('Email') [ok] | Input properly labeled |

| getByRole('navigation') [ok] | Landmark exists |

| locator('.submit-btn') [!] | May lack accessible name |

Key Workflows

Automated Axe Scan (WCAG 2.2 AA)

import AxeBuilder from "@axe-core/playwright";
import { test, expect } from "@playwright/test";

test("page has no WCAG 2.2 AA violations", async ({ page }) => {
  await page.goto("/");

  const results = await new AxeBuilder({ page })
    .withTags(["wcag2a", "wcag2aa", "wcag21a", "wcag21aa", "wcag22a", "wcag22aa"])
    .analyze();

  expect(results.violations).toEqual([]);
});

Scoped Axe Scan (Component-Level)

test("form component is accessible", async ({ page }) => {
  await page.goto("/contact");

  const results = await new AxeBuilder({ page })
    .include("#contact-form") // Scope to specific component
    .withTags(["wcag2a", "wcag2aa", "wcag21a", "wcag21aa", "wcag22a", "wcag22aa"])
    .analyze();

  expect(results.violations).toEqual([]);
});

Keyboard Navigation Test

test("form is keyboard navigable", async ({ page }) => {
  await page.goto("/login");

  // Tab to first field
  await page.keyboard.press("Tab");
  await expect(page.getByLabel("Email")).toBeFocused();

  // Tab to password
  await page.keyboard.press("Tab");
  await expect(page.getByLabel("Password")).toBeFocused();

  // Tab to submit button
  await page.keyboard.press("Tab");
  await expect(page.getByRole("button", { name: "Sign in" })).toBeFocused();

  // Submit with Enter
  await page.keyboard.press("Enter");
  await expect(page).toHaveURL(/dashboard/);
});

Dialog Focus Management

test("dialog traps and returns focus", async ({ page }) => {
  await page.goto("/settings");
  const trigger = page.getByRole("button", { name: "Delete account" });

  // Open dialog
  await trigger.click();
  const dialog = page.getByRole("dialog");
  await expect(dialog).toBeVisible();

  // Focus should be inside dialog
  await expect(dialog.getByRole("button", { name: "Cancel" })).toBeFocused();

  // Tab should stay trapped in dialog
  await page.keyboard.press("Tab");
  await expect(dialog.getByRole("button", { name: "Confirm" })).toBeFocused();
  await page.keyboard.press("Tab");
  await expect(dialog.getByRole("button", { name: "Cancel" })).toBeFocused();

  // Escape closes and returns focus to trigger
  await page.keyboard.press("Escape");
  await expect(dialog).toBeHidden();
  await expect(trigger).toBeFocused();
});

Skip Link Validation

test("skip link moves focus to main content", async ({ page }) => {
  await page.goto("/");

  // First Tab should focus skip link
  await page.keyboard.press("Tab");
  const skipLink = page.getByRole("link", { name: /skip to (main|content)/i });
  await expect(skipLink).toBeFocused();

  // Activating skip link moves focus to main
  await page.keyboard.press("Enter");
  await expect(page.locator('#main, [role="main"]').first()).toBeFocused();
});

POUR Principles Reference

| Principle | Focus Areas | Example Tests |

| ------------------ | ----------------------------------------- | ------------------------------------------------- |

| Perceivable | Alt text, captions, contrast, structure | Image alternatives, color contrast ratio |

| Operable | Keyboard, focus, timing, navigation | Tab order, focus visibility, skip links |

| Understandable | Labels, instructions, errors, consistency | Form labels, error messages, predictable behavior |

| Robust | Valid HTML, ARIA, name/role/value | Semantic structure, accessible names |

Axe-Core Tags

Default: wcag2a, wcag2aa, wcag21a, wcag21aa, wcag22a, wcag22aa (WCAG 2.2 AA). Use best-practice for additional checks. See references/axe-tags-reference.md for full tag list.

Exception Handling

When exceptions are unavoidable:

• Scope narrowly - specific component/route only
• Document impact - which WCAG criterion, user impact
• Set expiration - owner + remediation date
• Track ticket - link to remediation issue

// [no] Avoid: Global rule disable
new AxeBuilder({ page }).disableRules(["color-contrast"]);

// [ok] Better: Scoped exclusion with documentation
new AxeBuilder({ page })
  .exclude("#third-party-widget") // Known issue: JIRA-1234, fix by Q2
  .withTags(["wcag2a", "wcag2aa", "wcag21a", "wcag21aa", "wcag22a", "wcag22aa"])
  .analyze();

Troubleshooting

| Problem | Cause | Solution |

| ------------------------------------------------- | ------------------------------ | --------------------------------------- |

| Axe finds 0 violations but app fails manual audit | Automation covers ~30-40% | Add manual testing checklist |

| False positive on dynamic content | Content not fully rendered | Wait for stable state before scan |

| Color contrast fails incorrectly | Background image/gradient | Use exclude for known false positives |

| Cannot find element by role | Missing semantic HTML | Fix markup - this is a real bug |

| Focus not visible | Missing :focus styles | Add visible focus indicator CSS |

| Dialog focus not trapped | Missing focus trap logic | Implement focus trap (see snippets) |

| Skip link doesn't work | Target missing tabindex="-1" | Add tabindex to main content |

CLI Quick Reference

| Command | Description |

| ----------------------------------- | -------------------------------------- |

| npx playwright test --grep "a11y" | Run accessibility tests only |

| npx playwright test --headed | Run with visible browser for debugging |

| npx playwright test --debug | Step through with Inspector |

| PWDEBUG=1 npx playwright test | Debug mode with pause |

Red Flags

• Treating a clean axe scan as full WCAG conformance — automation covers only ~30-40% of criteria.
• Globally disabling rules (e.g., color-contrast) instead of scoped .exclude() with a documented ticket.
• Scanning before the page reaches a stable state — async content yields false "0 violations".
• Skipping keyboard/focus tests because axe passed — focus order and traps need explicit tests.

References

| Document | Content |

| -------------------------------------------------------------------------------- | ------------------------------------------------ |

| Snippets: Setup & Scanning | axe-core setup, helper, and scanning patterns |

| Snippets: Keyboard, Focus, Semantic | Keyboard navigation, focus management, semantic structure |

| Snippets: Visual, Names, Checklist | Visual accessibility, accessible names, critical pages |

| WCAG 2.2 AA Checklist | Manual audit checklist by POUR principle |

| ARIA Patterns: Widgets Part 1 | Fundamentals, dialog, tabs, menu widgets |

| ARIA Patterns: Widgets Part 2 | Accordion, combobox, live regions, tooltip |

| ARIA Patterns: Mistakes & Reference | Common ARIA mistakes and roles quick reference |

External Resources

| Resource | URL |

| ---------------------------- | --------------------------------------- |

| WCAG 2.2 Specification | https://www.w3.org/TR/WCAG22/ |

| WCAG Quick Reference | https://www.w3.org/WAI/WCAG22/quickref/ |

| WAI-ARIA Authoring Practices | https://www.w3.org/WAI/ARIA/apg/ |

| axe-core Rules | https://dequeuniversity.com/rules/axe/ |

Verification

• [ ] axe-core audit passes — AxeBuilder.analyze() returns zero critical violations
• [ ] Keyboard navigation tested — All interactive elements reachable via Tab; focus order is logical
• [ ] Color contrast sufficient — WCAG 2.2 AA minimum contrast ratios met (4.5:1 normal text, 3:1 large text)
• [ ] WCAG 2.2 AA conformance — Tags wcag22a/wcag22aa included in scans (focus-not-obscured, dragging movements, target-size minimums)