How to mock an instance of elasticsearch in Node.js?

Question

I am using elasticsearch and would like to write a unit test for the following code:

import * as elasticsearch from "elasticsearch";
import config from "../config";

const client = new elasticsearch.Client({
  host: config.elasticsearch.host,
  log: "trace"
});

export function index(data) {
    return new Promise((resolve, reject) => {
        client.create({
            index: "myindex",
            type: "mytype",
            id: booking.urn,
            body: data
        }).then(resolve, reject);
    });
}

I am familiar with mocha and sinon, however I don't know of a good pattern to use to stub\mock client.create in this case.

Can anyone suggest an approach that I could use?

as an FYI : I ended up following something like this : slmyers.github.io/elasticsearch/javascript/testing/2017/04/04/…. Maybe a bit different from your approach depending on implementation. — blo0p3r
– blo0p3r, Commented Jun 6, 2017 at 14:22

luboskrnac · Accepted Answer · 2017-02-09 12:02:09Z

9

One possible option is to use proxyquire + sinon combo

Sinon will fake Client:

const FakeClient = sinon.stub();
FakeClient.prototype.create = sinon.stub().returns("your data");
var fakeClient = new FakeClient();
console.log(fakeClient.create()); // -> "your data"

Such fake client can be passed into module under test by injection via proxyquire:

import proxyquire from 'proxyquire';
const index = proxyquire('./your/index/module', {
  'elasticsearch': { Client: FakeClient }
});

answered Feb 9, 2017 at 12:02

luboskrnac

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1nstinct · Accepted Answer · 2018-07-03 05:52:05Z

The answer of luboskrnac will works if you are trying to proxiquire module that doesn't wrap elasticsearch client, otherwise you need to proxiquire nested elasticsearch client.

// controller.spec.js

const FakeClient = {};    
FakeClient.search = () => {};
sinon.stub(FakeClient, 'search').callsFake((params, cb) => cb(null, {
    hits: {
        hits: [{
            _source: {
                id: '95254ea9-a0bd-4c26-b5e2-3e9ef819571d',
            },
        }],
    },
}));

controller = proxyquire('./controller', {
    '../components/es.wrapper': FakeClient,
    '@global': true,
});

wrapper

// components/es.wrapper.js

const elasticsearch = require('elasticsearch');

const client = new elasticsearch.Client({
    host: process.env.ELASTICSEARCH_HOST,
});

const wrapper = (method, params, callback) => {
    if (process.env.NODE_ENV === 'development') {
        params.index = `dev_${params.index}`;
    }
    return client[method](params, callback);
};

// Wrap ES client methods with dev env prefix
module.exports = {
    search: (params, callback) => {
        return wrapper('search', params, callback);
    },
}

controller

// controller.js
const es = require('../components/es.wrapper');

module.exports = {
    search: (req, res, next) => {
         ....
         es.search(...)
         ....
    }
}

Pistos · Accepted Answer · 2019-04-11 14:32:00Z

0

I had success using https://www.npmjs.com/package/nock , mocking the calls to the elasticsearch host at port 9200.

answered Apr 11, 2019 at 14:32

Pistos

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1 Comment

jamis0n Over a year ago

Can you share a working example? I'm trying nock("https://xxx-yyy-zzz.us-east-2.es.amazonaws.com:9200").post("/*") and getting an SSL error. Not sure the best way to debug.

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