如何在javascript中将从mongo db检索到的对象传递给测试

npm install mongoose jest

// db.js
const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

const userSchema = new mongoose.Schema({
  name: String,
  email: String
});

const User = mongoose.model('User', userSchema);

module.exports = User;

// userService.js
const User = require('./db');

async function getUserById(id) {
  try {
    const user = await User.findById(id);
    return user;
  } catch (error) {
    throw error;
  }
}

module.exports = { getUserById };

// userService.test.js
const { getUserById } = require('./userService');
const mongoose = require('mongoose');

beforeAll(async () => {
  await mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });
});

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

test('getUserById should return a user', async () => {
  const user = await getUserById('someUserId');
  expect(user).toBeDefined();
  expect(user.name).toBe('ExpectedUserName');
});