[CHORE] Add axe-core WCAG 2.2 AA accessibility tests + DuckDB query tests to CI

.github/workflows/a11y.yml

@@ -0,0 +1,43 @@
+---
+name: Accessibility
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: a11y-${{ github.event.number || github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  a11y:
+    name: WCAG 2.2 AA
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+        with:
+          persist-credentials: false
+
+      - name: Set up Node.js
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version-file: package.json
+
+      - name: Configure sustainable npm
+        uses: lowlydba/sustainable-npm@31d51025884f424f58f22e4e6578178bb4e79632 # v3.0.0
+
+      - name: Install NPM dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+
+      - name: Install Playwright browser
+        run: npx playwright install chromium --with-deps
+
+      - name: Run accessibility tests
+        run: npm run test:a11y

__tests__/a11y.test.mjs

@@ -0,0 +1,102 @@
+/**
+ * WCAG 2.2 AA accessibility tests using Node's built-in test runner.
+ * Requires a built `build/` directory — run `npm run build` first.
+ * Run with: npm run test:a11y
+ */
+
+import { test, before, after } from 'node:test';
+import assert from 'node:assert/strict';
+import { createServer } from 'node:http';
+import { readFile, access } from 'node:fs/promises';
+import { extname, join } from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { chromium } from 'playwright';
+import AxeBuilder from '@axe-core/playwright';
+
+const __dirname = fileURLToPath(new URL('.', import.meta.url));
+const BUILD_DIR = join(__dirname, '..', 'build');
+const PORT = 3778;
+const BASE_URL = `http://localhost:${PORT}`;
+
+const MIME = {
+  '.html': 'text/html',
+  '.js': 'application/javascript',
+  '.mjs': 'application/javascript',
+  '.css': 'text/css',
+  '.png': 'image/png',
+  '.svg': 'image/svg+xml',
+  '.woff2': 'font/woff2',
+  '.json': 'application/json',
+};
+
+let server, browser;
+
+before(async () => {
+  await access(join(BUILD_DIR, 'index.html')).catch(() => {
+    throw new Error(`build/index.html not found — run 'npm run build' before running accessibility tests`);
+  });
+
+  // ponytail: minimal static file server, falls back to index.html for Docusaurus client-side routing
+  server = createServer(async (req, res) => {
+    const urlPath = req.url.split('?')[0];
+    const filePath = join(BUILD_DIR, urlPath === '/' ? 'index.html' : urlPath);
+    try {
+      const data = await readFile(filePath);
+      res.writeHead(200, { 'Content-Type': MIME[extname(filePath)] ?? 'application/octet-stream' });
+      res.end(data);
+    } catch {
+      try {
+        const data = await readFile(join(BUILD_DIR, 'index.html'));
+        res.writeHead(200, { 'Content-Type': 'text/html' });
+        res.end(data);
+      } catch {
+        res.writeHead(404);
+        res.end('Not found');
+      }
+    }
+  });
+  await new Promise((resolve) => server.listen(PORT, resolve));
+  browser = await chromium.launch();
+});
+
+after(async () => {
+  await browser?.close();
+  await new Promise((resolve) => server.close(resolve));
+});
+
+function formatViolations(violations, label) {
+  if (violations.length === 0) return;
+  const detail = violations
+    .map((v) =>
+      `[${v.impact}] ${v.id}: ${v.description}\n` +
+      v.nodes.map((n) => `  • ${n.target}`).join('\n')
+    )
+    .join('\n\n');
+  assert.fail(`${violations.length} WCAG 2.2 AA violation(s) — ${label}:\n\n${detail}`);
+}
+
+async function runAxe(url) {
+  const context = await browser.newContext();
+  const page = await context.newPage();
+  try {
+    await page.goto(`${BASE_URL}${url}`, { waitUntil: 'domcontentloaded' });
+    await page.waitForSelector('main', { timeout: 10000 });
+    const { violations } = await new AxeBuilder({ page })
+      .withTags(['wcag2a', 'wcag2aa', 'wcag21a', 'wcag21aa', 'wcag22aa'])
+      .analyze();
+    return violations;
+  } finally {
+    await context.close();
+  }
+}
+
+const PAGES = [
+  { path: '/', label: 'homepage' },
+  { path: '/docs/', label: 'docs index' },
+];
+
+for (const { path, label } of PAGES) {
+  test(`${label} passes WCAG 2.2 AA`, async () => {
+    formatViolations(await runAxe(path), label);
+  });
+}

package.json

@@ -20,6 +20,7 @@
     "format": "prettier --write .",
     "format:check": "prettier --check .",
     "test": "vitest run",
+    "test:a11y": "node --test --test-reporter=spec __tests__/a11y.test.mjs",
     "test:watch": "vitest",
     "typecheck": "tsc --noEmit"
   },
@@ -40,6 +41,7 @@
     "react-dom": "^19.2.7"
   },
   "devDependencies": {
+    "@axe-core/playwright": "^4.11.3",
     "@docusaurus/module-type-aliases": "^3.10.0",
     "@docusaurus/types": "^3.10.0",
     "@eslint/js": "^10.0.0",
@@ -52,6 +54,7 @@
     "globals": "^17.6.0",
     "jsdom": "^29.1.1",
     "markdownlint-cli": "^0.48.0",
+    "playwright": "^1.61.0",
     "prettier": "^3.8.4",
     "typescript": "^6.0.3",
     "vitest": "^4.1.8"