Add test suite for highlight.js Djot grammar (#100)

* Add test suite for highlight.js Djot grammar

- Add docs/tests/ with Node.js test suite using highlight.js
- 50 test cases covering all Djot syntax elements
- Add GitHub workflow to run tests on PRs affecting hljs-djot.js

* Expand hljs test suite to 118 comprehensive tests

Cover all Djot syntax elements:
- Headings (levels 1-6)
- Emphasis/strong variations
- Code (inline, double/triple backtick, fences)
- Links (inline, reference, shortcut, autolink, email)
- Images (with titles, attributes)
- Lists (all markers, numbered, task, indented)
- Blockquotes, divs (with 4+ colons)
- Tables (rows, separators, alignment)
- Comments (inline, fenced)
- Highlight, insert, delete
- Super/subscript (shorthand and braced)
- Math (inline, display)
- Definitions (reference, footnote, abbreviation)
- Attributes (class, id, key-value, complex)
- Horizontal rules, symbols, smart punctuation
- Escapes, raw format, captions, line blocks
- Frontmatter, hard line breaks
- Edge cases with multiple elements

Author: dereuromark

.github/workflows/test-hljs.yml

@@ -0,0 +1,35 @@
+name: Test Highlight.js Grammar
+
+on:
+  push:
+    branches: [master]
+    paths:
+      - 'docs/public/assets/hljs-djot.js'
+      - 'docs/tests/**'
+  pull_request:
+    paths:
+      - 'docs/public/assets/hljs-djot.js'
+      - 'docs/tests/**'
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: docs/tests/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+        working-directory: docs/tests
+
+      - name: Run highlight.js grammar tests
+        run: npm test
+        working-directory: docs/tests

.gitignore

@@ -19,6 +19,7 @@
 
 # Documentation
 /docs/node_modules/
+/docs/tests/node_modules/
 /docs/.vitepress/cache/
 /docs/.vitepress/dist/
 /docs/.vitepress/grammars/

docs/tests/package-lock.json

@@ -0,0 +1,12 @@
+{
+  "name": "djot-hljs-tests",
+  "version": "1.0.0",
+  "description": "Tests for Djot highlight.js grammar",
+  "type": "module",
+  "scripts": {
+    "test": "node test-hljs.mjs"
+  },
+  "devDependencies": {
+    "highlight.js": "^11.9.0"
+  }
+}