lumen-generators/lumen-test/app/Http/routes.php

<?php

/*
|--------------------------------------------------------------------------
| Application Routes
|--------------------------------------------------------------------------
|
| Here is where you can register all of the routes for an application.
| It is a breeze. Simply tell Lumen the URIs it should respond to
| and give it the Closure to call when that URI is requested.
|
*/

$app->get("/", function () use ($app) {
    return $app->welcome();
});