test: regression coverage for add-frontmatter glob crash

package.json

@@ -36,7 +36,7 @@
     "precheck:links": "npm run build",
     "seq": "bash -c 'for cmd in \"$@\"; do npm run $cmd || exit 1; done' - ",
     "serve": "npm run docus:serve",
-    "test:unit": "node --experimental-strip-types --test 'lib/**/*.test.mts'",
+    "test:unit": "node --experimental-strip-types --test 'lib/**/*.test.mts' 'scripts/**/*.test.mjs'",
     "test": "npm run check && npm run test:unit",
     "typecheck": "tsc",
     "update:packages": "npx npm-check-updates -u"
@@ -57,6 +57,7 @@
     "@docusaurus/tsconfig": "3.10.2",
     "@docusaurus/types": "3.10.2",
     "cspell": "^10.0.1",
+    "glob": "^14.0.5",
     "markdown-link-check": "3.15.0",
     "markdownlint-cli": "^0.49.1",
     "markdownlint": "^0.41.1",

scripts/add-frontmatter.test.mjs

@@ -0,0 +1,85 @@
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import { execFileSync } from 'node:child_process';
+import { mkdtemp, mkdir, readFile, writeFile, rm } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import url from 'node:url';
+
+const __dirname = path.dirname(url.fileURLToPath(import.meta.url));
+const scriptPath = path.join(__dirname, 'add-frontmatter.mjs');
+
+/**
+ * Run add-frontmatter.mjs against a fresh temp directory containing the
+ * given docs/*.md fixtures, then return the resulting file contents.
+ */
+async function runOnFixture(fileContents) {
+  const dir = await mkdtemp(path.join(tmpdir(), 'add-frontmatter-'));
+  try {
+    await mkdir(path.join(dir, 'docs'), { recursive: true });
+    for (const [name, content] of Object.entries(fileContents)) {
+      await writeFile(path.join(dir, 'docs', name), content);
+    }
+
+    execFileSync('node', [scriptPath], { cwd: dir });
+
+    const results = {};
+    for (const name of Object.keys(fileContents)) {
+      results[name] = await readFile(path.join(dir, 'docs', name), 'utf-8');
+    }
+    return results;
+  } finally {
+    await rm(dir, { recursive: true, force: true });
+  }
+}
+
+describe('add-frontmatter.mjs', () => {
+  it('resolves the glob dependency without crashing', () => {
+    // Regression guard: the script previously threw
+    // ERR_MODULE_NOT_FOUND for 'glob' immediately on startup because the
+    // dependency had been dropped from package.json.
+    assert.doesNotThrow(() => {
+      execFileSync('node', [scriptPath], { cwd: tmpdir() });
+    });
+  });
+
+  it('adds a title to a file with no frontmatter', async () => {
+    const results = await runOnFixture({
+      'no-frontmatter.md': '# Hello World\n\nSome content.\n',
+    });
+    assert.match(
+      results['no-frontmatter.md'],
+      /^---\ntitle: Hello World\n---\n/,
+    );
+    assert.match(results['no-frontmatter.md'], /Some content\./);
+  });
+
+  it('inserts a title above existing frontmatter keys when none is present', async () => {
+    const results = await runOnFixture({
+      'no-title.md':
+        '---\ndescription: a page\n---\n\n# My Page\n\nBody text.\n',
+    });
+    assert.match(
+      results['no-title.md'],
+      /^---\ntitle: My Page\ndescription: a page\n---\n/,
+    );
+  });
+
+  it('quotes a title that contains a colon', async () => {
+    const results = await runOnFixture({
+      'colon-title.md': '# Section: Details\n\nBody text.\n',
+    });
+    assert.match(
+      results['colon-title.md'],
+      /^---\ntitle: 'Section: Details'\n---\n/,
+    );
+  });
+
+  it('leaves a file with no heading unchanged (warns instead of crashing)', async () => {
+    const original = 'Just a paragraph with no heading.\n';
+    const results = await runOnFixture({
+      'no-heading.md': original,
+    });
+    assert.equal(results['no-heading.md'], original);
+  });
+});