fix: export hello() and avoid starting server during tests

Author: vedantoncloud

app.js

@@ -1,13 +1,26 @@
-const express = require("express");
+// app.js
+const express = require("express");
 const app = express();
 
+// keep the old test string for the unit test
+function hello() {
+  return "Hello from MyApp - dev";
+}
+
+// public route shows CI/CD message
 app.get("/", (req, res) => {
   res.send("Hello from MyApp - CI/CD Working!");
 });
 
-const PORT = process.env.PORT || 3000;
-app.listen(PORT, () => {
-  console.log(`Server running on port ${PORT}`);
-});
+// export the Express app and the hello() function for tests
+module.exports = { app, hello };
 
-module.exports = app;
+// Only start the server when this file is run directly (node app.js),
+// not when imported by tests (require).
+if (require.main === module) {
+  const PORT = process.env.PORT || 3000;
+  app.listen(PORT, () => {
+    // only log when actually starting the server
+    console.log(`Server running on port ${PORT}`);
+  });
+}