server.js

@@ -118,8 +118,11 @@ app.get('/api/dns/:domain', function (req, res, next) {
   dig.resolveJson(query, opts);
 });
 
-// curl -L http://localhost:3000/api/dns/example.com?type=A
-console.log("Listening on localhost:3000");
-app.listen(3000);
-console.log("Try this:");
-console.log("\tcurl -L 'http://localhost:3000/api/dns/example.com?type=A'");
+module.exports = app;
+if (require.main === module) {
+  // curl -L http://localhost:3000/api/dns/example.com?type=A
+  console.log("Listening on localhost:3000");
+  app.listen(3000);
+  console.log("Try this:");
+  console.log("\tcurl -L 'http://localhost:3000/api/dns/example.com?type=A'");
+}