Running multiple test files with chai where all of them use mongoDB memory server returns error

Question

So I want to test my integration with mongodb-memory-server. I created two seperate test files for different use cases, and both connect and disconnect to mongodb in before and after functions. This is my db.js file, where I have my connect and disconnect functions:

const { MongoMemoryServer } = require("mongodb-memory-server");
const mongoose = require("mongoose");

let mongoServer;

async function start() {
  mongoServer = await MongoMemoryServer.create();
  const mongoUri = mongoServer.getUri();
  await mongoose.connect(mongoUri);
}

async function stop() {
  await mongoose.disconnect();
  await mongoServer.stop();
}

module.exports = {
  start,
  stop,
};

And then in my test files this is how my before and after functions look:

before(async () => {
  await start();
});

after(async () => {
  await stop();
});

And when I run yarn test this is the error I get: MongooseError: Can't call `openUri()` on an active connection with different connection strings. Make sure you aren't calling `mongoose.connect()` multiple times. See: https://mongoosejs.com/docs/connections.html#multiple_connections So my question is, how to work around it? As I understand, tests create connections before the previous one is closed. I tried to create instances with different db names on mongoServer = await MongoMemoryServer.create() according to docs, but it didn't quite work. Do you guys have any recommendations?