testing后closures服务器和数据库连接

我有与mongo连接的koa服务器，并使用supertest模拟服务器和发送请求，作为testing框架。

const app = new Koa() ... export default app.listen(PORT, (err) => { if (err) console.log(err) if (!IS_TEST) { console.log(`Server running on port: ${PORT}`) } }) 

在成功完成testing或者服务器连接失败之后，koa服务器连接testing结束多久？

testing例子：

 import supertest from 'supertest' import mongoose from 'mongoose' import server from '../../../app/server' import User from '../../../app/models/user' const r = supertest.agent(server.listen()) afterEach(async (done) => { await mongoose.connection.db.dropDatabase() done() }) describe('Authorization', () => { describe('POST /signup', () => { const userData = { email: '[e-mail]', password: 111111, } test('success create user', (done) => { r .post(`/api/auth/signup`) .send(userData) .expect(200) .expect({ data: { email: userData.email, }, }) .end(done) }) test('fail of user create, password required', (done) => { const userData = { email: '[e-mail]', } r .post(`/api/auth/signup`) .send(userData) .expect(400) .expect({ errors: { password: 'Password required', }, }) .end(done) }) }) })