ioredis-mock

What is ioredis-mock?

ioredis-mock is a mock implementation of the ioredis library, which is used for interacting with Redis databases. This package is particularly useful for testing purposes, as it allows developers to simulate Redis operations without needing a real Redis server.

What are ioredis-mock's main functionalities?

Basic Redis Commands

This feature allows you to perform basic Redis commands such as SET and GET. The code sample demonstrates setting a key-value pair and then retrieving the value.

const Redis = require('ioredis-mock');
const redis = new Redis();

redis.set('key', 'value').then(() => {
  return redis.get('key');
}).then(value => {
  console.log(value); // 'value'
});

Pub/Sub

This feature allows you to use the publish/subscribe pattern. The code sample demonstrates subscribing to a channel and publishing a message to that channel.

const Redis = require('ioredis-mock');
const pub = new Redis();
const sub = new Redis();

sub.subscribe('channel', (err, count) => {
  pub.publish('channel', 'message');
});

sub.on('message', (channel, message) => {
  console.log(channel, message); // 'channel', 'message'
});

Transactions

This feature allows you to perform transactions using the MULTI command. The code sample demonstrates setting a key-value pair and then retrieving the value within a transaction.

const Redis = require('ioredis-mock');
const redis = new Redis();

redis.multi()
  .set('key', 'value')
  .get('key')
  .exec((err, results) => {
    console.log(results); // [[null, 'OK'], [null, 'value']]
  });

Other packages similar to ioredis-mock

redis-mock

redis-mock is another mock implementation of the Redis API. It provides a similar set of functionalities for testing purposes. However, it is generally considered less feature-rich and less actively maintained compared to ioredis-mock.

fakeredis

fakeredis is a pure Python implementation of the Redis API, which can be used for testing purposes. It is similar to ioredis-mock but is intended for use in Python environments rather than Node.js.

README

ioredis-mock ·

This library emulates ioredis by performing all operations in-memory. The best way to do integration testing against redis and ioredis is on a real redis-server instance. However, there are cases where mocking the redis-server is a better option.

Cases like:

• Your workflow already use a local redis-server instance for the dev server.
• You're on a platform without an official redis release, that's even worse than using an emulator.
• You're running tests on a CI, setting it up is complicated. If you combine it with CI that also run selenium acceptance testing it's even more complicated, as two redis-server instances on the same CI build is hard.
• The GitHub repo have bots that run the testing suite and is limited through npm package.json install scripts and can't fire up servers. (Having Greenkeeper notifying you when a new release of ioredis is out and wether your code breaks or not is awesome).

Check the compatibility table for supported redis commands.

Usage (try it in your browser)

var Redis = require('ioredis-mock');
var redis = new Redis({
  // `options.data` does not exist in `ioredis`, only `ioredis-mock`
  data: {
    user_next: '3',
    emails: {
      '[e-mail]': '1',
      '[e-mail]': '2',
    },
    'user:1': { id: '1', username: 'superman', email: '[e-mail]' },
    'user:2': { id: '2', username: 'batman', email: '[e-mail]' },
  },
});
// Basically use it just like ioredis

Configuring Jest

Use the jest specific bundle when setting up mocks:

jest.mock('ioredis', () => require('ioredis-mock/jest'));

The ioredis-mock/jest bundle inlines imports from ioredis that ioredis-mock rely on. Thus you can map ioredis import identifiers to ioredis-mock/jest without dealing with circular issues.

Pub/Sub channels

We also support redis publish/subscribe channels (just like ioredis). Like ioredis, you need two clients:

• the pubSub client for subcriptions and events, which can only be used for subscriptions
• the usual client for issuing 'synchronous' commands like get, publish, etc

var Redis = require('ioredis-mock');
var redisPubSub = new Redis();
// create a second Redis Mock (connected to redisPubSub)
var redisSync = redisPubSub.createConnectedClient();
redisPubSub.on('message', (channel, message) => {
  expect(channel).toBe('emails');
  expect(message).toBe('[e-mail]');
  done();
});
redisPubSub.subscribe('emails');
redisSync.publish('emails', '[e-mail]');

Promises

By default, ioredis-mock uses the native Promise library. If you need (or prefer) bluebird promises, set Redis.Promise:

var Promise = require('bluebird');
var Redis = require('ioredis-mock');

Redis.Promise = Promise;

Lua scripting

You can use the defineCommand to define custom commands using lua or eval to directly execute lua code.

In order to create custom commands, using lua scripting, ioredis exposes the defineCommand method.

You could define a custom command MULTIPLY which accepts one key and one argument. A redis key, where you can get the multiplicand, and an argument which will be the multiplicator:

var Redis = require('ioredis-mock');
const redis = new Redis({ data: { 'k1': 5 } });
const commandDefinition: { numberOfKeys: 1, lua: 'return KEYS[1] * ARGV[1]' };
redis.defineCommand('MULTIPLY', commandDefinition) // defineCommand(name, definition)
  // now we can call our brand new multiply command as an ordinary command
  .then(() => redis.multiply('k1', 10));
  .then(result => {
    expect(result).toBe(5 * 10);
  })

You can also achieve the same effect by using the eval command:

var Redis = require('ioredis-mock');
const redis = new Redis({ data: { k1: 5 } });
const result = redis.eval(`return redis.call("GET", "k1") * 10`);
expect(result).toBe(5 * 10);

note we are calling the ordinary redis GET command by using the global redis object's call method.

As a difference from ioredis we currently don't support:

• dynamic key number by passing the number of keys as the first argument of the command.
• automatic definition of the custom command buffer companion (i.e. for the custom command multiply the multiplyBuffer which returns values using Buffer.from(...))
• the evalsha command
• the script command

Cluster(Experimental)

Work on Cluster support has started, the current implementation is minimal and PRs welcome #359

var Redis = require('ioredis-mock');

const cluster = new Redis.Cluster(['redis://localhost:7001']);
const nodes = cluster.nodes;
expect(nodes.length).toEqual(1);

Roadmap

This project started off as just an utility in another project and got open sourced to benefit the rest of the ioredis community. This means there's work to do before it's feature complete:

• Setup testing suite for the library itself.
• Refactor to bluebird promises like ioredis, support node style callback too.
• Implement remaining basic features that read/write data.
• Implement ioredis argument and reply transformers.
• Connection Events
• Offline Queue
• Pub/Sub
• Error Handling
• Implement remaining commands

I need a feature not listed here

Just create an issue and tell us all about it or submit a PR with it! 😄