"ReferenceError: You are trying to `import` a file after the Jest environment has been torn down" when using jest with mongoose

Question

i have two test files that connect with mongoose, the problem started when i added the second one i tried to use jest.useFakeTimers() after imports but nothing changed

here is the test file

const mongoose = require("mongoose");
const supertest = require("supertest");
const app = require("../app");
const api = supertest(app);
const User = require("../models/user");
const bcrypt = require("bcryptjs");

describe("adding users", () => {
  beforeEach(async () => {
    await User.deleteMany({});

    const passwordHash = await bcrypt.hash("sekret", 10);
    const user = new User({ username: "root", passwordHash });

    await user.save();
  });
  test("adding users successfuly", async () => {
    const newUser = {
      name: "john oliver",
      username: "karana",
      password: "ooiiu",
    };
    await api.post("/api/users").send(newUser).expect(200);
  });
});

afterAll(() => {
  mongoose.connection.close();
});

and here is the mongoose model

const mongoose = require("mongoose");
const uniqueValidator = require("mongoose-unique-validator");

const userSchema = new mongoose.Schema({
  name: String,
  username: {
    type: String,
    unique: true,
    minlength: 3,
  },
  passwordHash: String,
});
userSchema.plugin(uniqueValidator);

userSchema.set("toJSON", {
  transform: (document, returnedObject) => {
    returnedObject.id = returnedObject._id.toString();
    delete returnedObject._id;
    delete returnedObject.__v;
    delete returnedObject.passwordHash;
  },
});

module.exports = mongoose.model("User", userSchema);

here is the controller

const bcrypt = require("bcryptjs");
const usersRouter = require("express").Router();
const User = require("../models/user");

usersRouter.get("/", async (req, res) => {
  const users = await User.find({});
  res.json(users);
});

usersRouter.post("/", async (req, res, next) => {
  const body = req.body;

  if (body.password.length >= 3) {
    const saltRounds = 10;
    const passwordHash = await bcrypt.hash(body.password, saltRounds);

    const user = new User({
      name: body.name,
      username: body.username,
      passwordHash,
    });

    try {
      const result = await user.save();
      res.status(200).json(result);
    } catch (err) {
      next(err);
    }
  } else {
    res
      .status(400)
      .json({ error: "password must be atleast 3 charecters long" });
  }
});

module.exports = usersRouter;

*and there router is * app.use("/api/users", usersRouter); as written in the app.js files.

here is the error am getting

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\oussama\Desktop\web-projects\fullstackopen-part4\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\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\readable-stream\lib\_stream_readable.js:111:25)
    at BufferList.Readable (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\readable-stream\lib\_stream_readable.js:183:25)
    at BufferList.Duplex (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\readable-stream\lib\_stream_duplex.js:67:12)
    at new BufferList (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\bl\bl.js:33:16)
    at new MessageStream (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\mongodb\lib\cmap\message_stream.js:35:21)
    at new Connection (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\mongodb\lib\cmap\connection.js:54:28)
    at C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\mongodb\lib\core\connection\connect.js:36:29
    at callback (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\mongodb\lib\core\connection\connect.js:280:5)
    at TLSSocket.connectHandler (C:\Users\oussama\Desktop\web-projects\fullstackopen-part4\node_modules\mongodb\lib\core\connection\connect.js:325:5)
    at Object.onceWrapper (events.js:421:28)
    at TLSSocket.emit (events.js:315:20)
    at TLSSocket.onConnectSecure (_tls_wrap.js:1530:10)
    at TLSSocket.emit (events.js:315:20)
    at TLSSocket._finishInit (_tls_wrap.js:936:8)
    at TLSWrap.ssl.onhandshakedone (_tls_wrap.js:710:12)

the error happen after saving the data (users) to mongoDB. thanks in advance.

Answer 1

I resolved this by using the jest-mongodb preset which supplies all the async config necessary for Jest to run smoothly with MongoDB.

Note that Mongoose doc warns against using jest.useFakeTimers() because they "stub out global functions like setTimeout() and setInterval(), which causes problems when an underlying library uses these functions"