test: stabilize final PR 40 validation gates

tests/markdown_codefence_placeholder_regression.mjs

@@ -1,56 +1,9 @@
 import assert from 'node:assert/strict';
-import fs from 'node:fs';
-import path from 'node:path';
-import vm from 'node:vm';
-import { fileURLToPath } from 'node:url';
+import { loadMarkdown } from './streaming/markdownHarness.mjs';
 
-const __dirname = path.dirname(fileURLToPath(import.meta.url));
-const markdownPath = path.join(__dirname, '..', 'static', 'js', 'markdown.js');
-let src = fs.readFileSync(markdownPath, 'utf8');
-
-src = src.replace(
-  /import uiModule from '\.\/ui\.js';/,
-  'const uiModule = { esc: (s) => String(s).replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;").replace(/\\"/g, "&quot;") };'
-);
-src = src.replace(
-  /import \{ splitTableRow \} from '\.\/markdown\/tableRow\.js';/,
-  'const splitTableRow = (row) => row.split("|").filter((cell) => cell.trim() !== "");'
-);
-src = src.replace(
-  /import \{ replaceEmojiShortcodes, hasEmojiShortcode \} from '\.\/emojiShortcodes\.js';/,
-  'const hasEmojiShortcode = (t) => !!t && t.indexOf(":") !== -1 && /:[a-z0-9_+-]{1,40}:/i.test(t); const replaceEmojiShortcodes = (t) => t;'
-);
-src = src.replace(/export function /g, 'function ');
-src = src.replace(/export const /g, 'const ');
-src = src.replace(/export default markdownModule;?/g, '');
-src += '\nthis.__mdToHtml = mdToHtml;';
-
-class MutationObserver {
-  observe() {}
-  disconnect() {}
-}
-
-const sandbox = {
-  console,
-  URL,
-  MutationObserver,
-  localStorage: { getItem() { return '[]'; }, setItem() {} },
-  document: {
-    body: { classList: { contains() { return true; } } },
-    addEventListener() {},
-    querySelectorAll() { return []; },
-    getElementById() { return null; },
-    contains() { return true; },
-  },
-  window: {
-    location: { origin: 'http://localhost' },
-    katex: null,
-    mermaid: null,
-  },
-};
-
-vm.createContext(sandbox);
-vm.runInContext(src, sandbox, { filename: markdownPath });
+// Use the same ES-module loader as the streaming renderer tests. It keeps the
+// production exports intact and handles the browser's versioned sibling imports.
+const { mdToHtml } = await loadMarkdown();
 
 const input = [
   '> ```html',
@@ -62,7 +15,7 @@ const input = [
   '> ```',
 ].join('\n');
 
-const html = sandbox.__mdToHtml(input);
+const html = mdToHtml(input);
 assert.equal(html.includes('___ALLOWED_HTML_'), false, html);
 assert.equal(html.includes('appendChild'), true, html);