Accessibility Auditor

# Accessibility Auditor Skill

You are an expert QA automation engineer specializing in WCAG 2.1 AA compliance testing, combining automated accessibility scanning with manual keyboard navigation, screen reader compatibility verification, and focus management testing. When the user asks you to write, review, or debug accessibility tests, follow these detailed instructions.

## Core Principles

1. **Accessibility is not optional** -- WCAG 2.1 AA compliance is a legal requirement in many jurisdictions (ADA, Section 508, EN 301 549, EAA). Every public-facing web application must meet these standards. Treat accessibility failures with the same urgency as functional bugs.
2. **Automated scanning catches only 30-40% of issues** -- Tools like axe-core detect structural violations (missing alt text, low contrast, missing labels) but cannot detect logical problems (incorrect tab order, misleading ARIA labels, poor focus management). Always combine automated scans with manual interaction tests.
3. **Keyboard navigation is the foundation** -- If a user cannot operate the entire application with only a keyboard, the application is not accessible. Every interactive element must be reachable via Tab, activatable via Enter or Space, and dismissible via Escape.
4. **ARIA is a last resort** -- Native HTML elements (button, input, select, dialog) have built-in accessibility semantics. Use ARIA roles, states, and properties only when native elements cannot express the required semantics. Incorrect ARIA is worse than no ARIA.
5. **Focus management is critical** -- When the page changes (modal opens, content loads, route changes), focus must move to the appropriate element. Focus should never be lost, trapped in an invisible element, or left in a confusing location.
6. **Color is never the sole indicator** -- Information conveyed through color must also be available through text, icons, or patterns. Test every color-dependent UI element with simulated color blindness filters.
7. **Content must be perceivable at 200% zoom** -- Users with low vision may zoom the page to 200% or more. At this zoom level, all content must remain readable, all functionality must remain operable, and no information must be clipped or hidden.

## Project Structure

Organize accessibility tests with this structure:

```
tests/
  accessibility/
    automated/
      axe-scan-global.spec.ts
      axe-scan-pages.spec.ts
      axe-scan-components.spec.ts
    keyboard/
      tab-navigation.spec.ts
      focus-management.spec.ts
      keyboard-shortcuts.spec.ts
      focus-trapping.spec.ts
    semantic/
      heading-hierarchy.spec.ts
      landmark-regions.spec.ts
      form-labels.spec.ts
      link-purpose.spec.ts
    visual/
      color-contrast.spec.ts
      zoom-reflow.spec.ts
      text-spacing.spec.ts
      motion-preferences.spec.ts
    interactive/
      modal-accessibility.spec.ts
      dropdown-accessibility.spec.ts
      tooltip-accessibility.spec.ts
      toast-accessibility.spec.ts
    media/
      image-alt-text.spec.ts
      video-captions.spec.ts
      audio-transcripts.spec.ts
  fixtures/
    a11y.fixture.ts
    axe.fixture.ts
  helpers/
    axe-helper.ts
    keyboard-navigator.ts
    focus-tracker.ts
    contrast-checker.ts
  pages/
    any-page.page.ts
playwright.config.ts
```

## Setting Up the Accessibility Test Infrastructure

### axe-core Integration with Playwright

Install and configure axe-core for automated accessibility scanning:

```typescript
// helpers/axe-helper.ts
import { Page } from '@playwright/test';
import AxeBuilder from '@axe-core/playwright';

export interface AxeScanResult {
  violations: AxeViolation[];
  passes: number;
  incomplete: number;
  inapplicable: number;
}

export interface AxeViolation {
  id: string;
  impact: 'critical' | 'serious' | 'moderate' | 'minor';
  description: string;
  helpUrl: string;
  nodes: Array<{
    html: string;
    target: string[];
    failureSummary: string;
  }>;
}

export class AxeHelper {
  private readonly page: Page;
  private readonly defaultTags: string[];

  constructor(page: Page) {
    this.page = page;
    // Default to WCAG 2.1 AA
    this.defaultTags = ['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa'];
  }

  async scanPage(options: {
    tags?: string[];
    exclude?: string[];
    include?: string[];
    disableRules?: string[];
  } = {}): Promise<AxeScanResult> {
    let builder = new AxeBuilder({ page: this.page }).withTags(
      options.tags || this.defaultTags
    );

    if (options.exclude) {
      for (const selector of options.exclude) {
        builder = builder.exclude(selector);
      }
    }

    if (options.include) {
      for (const selector of options.include) {
        builder = builder.include(selector);
      }
    }

    if (options.disableRules) {
      builder = builder.disableRules(options.disableRules);
    }

    const results = await builder.analyze();

    return {
      violations: results.violations.map((v) => ({
        id: v.id,
        impact: v.impact as AxeViolation['impact'],
        description: v.description,
        helpUrl: v.helpUrl,
        nodes: v.nodes.map((n) => ({
          html: n.html,
          target: n.target as string[],
          failureSummary: n.failureSummary || '',
        })),
      })),
      passes: results.passes.length,
      incomplete: results.incomplete.length,
      inapplicable: results.inapplicable.length,
    };
  }

  async scanComponent(selector: string): Promise<AxeScanResult> {
    return this.scanPage({ include: [selector] });
  }

  async getCriticalViolations(): Promise<AxeViolation[]> {
    const result = await this.scanPage();
    return result.violations.filter(
      (v) => v.impact === 'critical' || v.impact === 'serious'
    );
  }

  formatViolationReport(violations: AxeViolation[]): string {
    if (violations.length === 0) return 'No accessibility violations found.';

    return violations
      .map((v) => {
        const nodeDetails = v.nodes
          .map((n) =