testServer.js

const Koa = require('koa');
const app = new Koa();
const router = require('koa-router')();

router.get('/', async (ctx, next) {
  const result = await new Promise( resolve => {
    setTimeout(() => {resolve('YES!!!') }, 500)   
  })
  ctx.body = result
});

app.use(routes.routes());
app.use(routes.allowedMethods());

app.listen(3000);