出现错误“错误：超时超过 2000 毫秒。对于异步测试和挂钩，确保调用了“done()”；”

 const expect = require('chai').expect;
const mongoose = require('mongoose');
const CONFIG_DEV_MONGODB = require('../../config/config.dev').DB_CONNECTION_URL;
describe('get the foo', () => {
    let handler;
    before(() => {
        process.env.DEPLOYMENT_STAGE = 'test';
        process.env.DB_CONNECTION_URL = CONFIG_DEV_MONGODB;
        handler = require('./get');
    after(() => {
        if (mongoose.connection) {
            mongoose.connection.close();
    it('validate getFeaturedProducts get request with storeid',function(done){
        //request has the sample data for event
        let request = require('../../test/fixtures/featureProductJSON');
        handler.getFeaturedProducts(request, {} , (error, result) => {
             expect(error).to.be.null;
             expect(result).to.be.not.null;
             done()
这是处理程序
module.exports.getFeaturedProducts = function (event, context, callback) {
    ..............
    .......
    mongoConnection.then( function() {
         return callback(null, 'test');
     }, function (error) {
        return return callback(true, null);;
谁能解释一下发生了什么
原文由 made_in_india 发布，翻译遵循 CC BY-SA 4.0 许可协议