unit test with sinon, mochai, chai, supertest

elasticsearch.js

const app = require('../../app');
const request = require('supertest');
const sinon = require('sinon');
const { expect } = require('chai');

const ElasticSearch = require('../../models/elasticsearch');

const url = '/api/search?q=money&page_id=333&lang=en';
describe('GET /api/search', () => {
    let sandbox;
    beforeEach(() => {
        sandbox = sinon.createSandbox();
    });

    it('should response with 500 when no result found', (done) => {
        sandbox.stub(ElasticSearch, 'find').resolves(false);
        request(app)
            .get(url)
            .end((err, res) => {
                if (err) done(err);
                expect(res.statusCode).to.be.equal(500);
                expect(res.body).to.eql({ error: true });
                expect(ElasticSearch.find.getCall(0).args).to.eql(['333', 'money', 'en']);
                done();
            });
    });

    it('should response with 200 when faq exists', (done) => {
        const result = {"hits":{"hits":[{"_source":{"qid":"QA.008","q":"How do I get a Bitcoin address?","a":"Create by yourself"}},{"_source":{"qid":"QA.009","q":"How do I become millionaire before 30?","a":"By visualization"}},{"_source":{"qid":"QA.002","q":"How can I create or cancel a recurring transaction?","a":"How can I create a recurring transaction?"}}]},"suggest":{"q-suggest":[{"text":"money","offset":0,"length":5,"options":[{"_source":{"qid":"QA.009","q":"How do I become millionaire before 30?","a":"By visualization"}},{"_source":{"qid":"QA.0010","q":"How do I get a Bitcoin address?","a":"By visualization"}},{"_source":{"qid":"QA.006","q":"How do I receive digital currency from another wallet?","a":"You can use your Coinbase wallet to receive supported digital currencies"}}]}],"a-suggest":[{"text":"money","offset":0,"length":5,"options":[{"_source":{"qid":"QA.002","q":"How can I create or cancel a recurring transaction?","a":"How can I create a recurring transaction?"}}]}]}};
        sandbox.stub(ElasticSearch, 'find').resolves(result);
        const data = [{"a":"By visualization","q":"How do I become millionaire before 30?","qid":"QA.009"},{"a":"By visualization","q":"How do I get a Bitcoin address?","qid":"QA.0010"},{"a":"You can use your Coinbase wallet to receive supported digital currencies","q":"How do I receive digital currency from another wallet?","qid":"QA.006"},{"a":"Create by yourself","q":"How do I get a Bitcoin address?","qid":"QA.008"},{"a":"How can I create a recurring transaction?","q":"How can I create or cancel a recurring transaction?","qid":"QA.002"}];
        request(app)
            .get(url)
            .end((err, res) => {
                if (err) done(err);
                expect(res.statusCode).to.be.equal(200);
                expect(res.body).to.eql({ data: data });
                expect(ElasticSearch.find.getCall(0).args).to.eql(['333', 'money', 'en']);
                done();
            });
    });
    
    afterEach(function () {
        sandbox.restore();
    });
});