Mongoose，Supertest：测试运行完成后一秒 Jest 没有退出

Question

我正在尝试使用 jest 和 supertest 来测试我的 node.js + express 应用程序。然而， 我不断收到错误消息“测试运行完成后一秒钟 Jest 没有退出。”

如果我从 app.js 中删除 mongoose.connect(...) 一切正常，但我需要数据库...

这是我的代码：

app.js

const express = require('express');
const mongoose = require('mongoose');
const keys = require('./config/keys');

mongoose.connect(keys.MONGO_URI, 
  { useNewUrlParser: true, useCreateIndex: true, useUnifiedTopology: true });

const app = express();

app.get('/user', (req, res) => {
  res.send("success");
})

//...

module.exports = app;

app.test.js

const mongoose = require('mongoose');
const app = require('../src/app');
const request = require('supertest');

describe('GET /user', function () {
    afterAll(() => mongoose.disconnect());
    it('has respononse status code 200', function (done) {
        request(app)
            .get('/user')
            .expect(200, done);
    });
});

错误信息：

> jest

 PASS  tests/app.test.js (6.798 s)
  GET /user
    √ has respononse status code 200 (22 ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        6.875 s, estimated 7 s
Ran all test suites.

Jest did not exit one second after the test run has completed.

This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with `--detectOpenHandles` to troubleshoot this issue.

ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.

      at BufferList.Readable (node_modules/readable-stream/lib/_stream_readable.js:179:22)
      at BufferList.Duplex (node_modules/readable-stream/lib/_stream_duplex.js:67:12)
      at new BufferList (node_modules/bl/bl.js:33:16)
      at new MessageStream (node_modules/mongodb/lib/cmap/message_stream.js:35:21)
      at new Connection (node_modules/mongodb/lib/cmap/connection.js:54:28)
C:\Users\XXX\server\node_modules\readable-stream\lib\_stream_readable.js:111
  var isDuplex = stream instanceof Duplex;
                        ^

TypeError: Right-hand side of 'instanceof' is not callable
    at new ReadableState (C:\Users\XXX\server\node_modules\readable-stream\lib\_stream_readable.js:111:25)
    at BufferList.Readable (C:\Users\XXX\server\node_modules\readable-stream\lib\_stream_readable.js:183:25)
    at BufferList.Duplex (C:\Users\XXX\server\node_modules\readable-stream\lib\_stream_duplex.js:67:12)
    at new BufferList (C:\Users\XXX\server\node_modules\bl\bl.js:33:16)      
    at new MessageStream (C:\Users\XXX\server\node_modules\mongodb\lib\cmap\message_stream.js:35:21)
    at new Connection (C:\Users\XXX\server\node_modules\mongodb\lib\cmap\connection.js:54:28)
    at C:\Users\XXX\server\node_modules\mongodb\lib\core\connection\connect.js:36:29
    at callback (C:\Users\XXX\server\node_modules\mongodb\lib\core\connection\connect.js:280:5)
    at TLSSocket.connectHandler (C:\Users\XXX\server\node_modules\mongodb\lib\core\connection\connect.js:325:5)
    at Object.onceWrapper (node:events:433:28)
    at TLSSocket.emit (node:events:327:20)
    at TLSSocket.onConnectSecure (node:_tls_wrap:1527:10)
    at TLSSocket.emit (node:events:327:20)
    at TLSSocket._finishInit (node:_tls_wrap:932:8)
    at TLSWrap.ssl.onhandshakedone (node:_tls_wrap:706:12)
npm ERR! code 1

我尝试过的事情：

• 我使用“--detectOpenHandles”运行 Jest，但它没有提供任何其他信息。
• 没有 app.listen(PORT)（我有一个单独的 server.js 文件）
• 我在 package.json 中添加了以下内容：

package.json

"jest": {
  "testEnvironment": "node"
}

Answer 1

显然，当我调用 mongoose.disconnect(); 时，mongoose 没有建立连接，这会导致所有错误，所以我将其添加到我的代码中：

beforeAll((done) => {
    if(!mongoose.connection.db){
        mongoose.connection.on('connected', done)
    } else {
        done();
    }
}, 20000);