Basic element added: anchor and port

tests/canvas-static-route.test.js

@@ -0,0 +1,29 @@
+const assert = require('assert');
+const fs = require('fs');
+const path = require('path');
+
+const root = path.resolve(__dirname, '..');
+const canvasHtml = fs.readFileSync(path.join(root, 'frontend', 'canvas.html'), 'utf8');
+const serverPy = fs.readFileSync(path.join(root, 'backend', 'server.py'), 'utf8');
+
+assert(
+  canvasHtml.includes('src="/canvas-helpers.js"'),
+  'canvas.html should request the canvas helper script from /canvas-helpers.js'
+);
+assert(
+  serverPy.includes("@app.route('/canvas-helpers.js')"),
+  'backend/server.py should serve /canvas-helpers.js'
+);
+assert(
+  serverPy.includes("send_from_directory(FRONTEND_DIR, 'canvas-helpers.js')") ||
+    serverPy.includes('send_from_directory(FRONTEND_DIR, "canvas-helpers.js")'),
+  'the /canvas-helpers.js route should serve frontend/canvas-helpers.js'
+);
+assert(
+  serverPy.includes('def no_cache_response(response):'),
+  'canvas assets should use an explicit no-cache response helper'
+);
+assert(
+  serverPy.includes('Cache-Control') && serverPy.includes('no-store'),
+  'canvas routes should prevent stale browser caches while the editor is changing'
+);