a fake redis for node.js

This module provides easy-to-use simulated instances of Redis to which you appear to be connected via the redis client by Matt Ranney. It helps with writing tests in two ways: your tests won't require an actual redis instance and you'll be able to safely run as many tests in parallel as you want.

Install:

npm install fakeredis 

You can use fakeredis as you would use node_redis, just changing the module name from redis to fakeredis:

var client = require("fakeredis").createClient(port, host);

Both parameters are optional, and only serve to determine if you want to reuse a an existing fakeredis instance or not. You can also just name your backends arbitrarily:

// Create a connection to a fresh fakeredis instance: var client = fakeredis.createClient("social stuff"); // Connect to the same backend via another simulated connection: var concurrentClient = fakeredis.createClient("social stuff");

By omitting both parameters, you simply create a new blank slate fakeredis instance:

var client = require("fakeredis").createClient();

In other words, every time you create a client specifying the same port and/or name you reuse the same simulated backend. This makes most sense when you need a concurrent client setup for some test, say because you need to publish / subscribe, or because you want to test something that's based on MULTI/EXEC and uses optimistic locking with WATCH/UNWATCH.

In any case, fakeredis is great for testing because you can run as many tests in parallel as you wish, and that's also why you'll generally be naming your clients in a way that ensures tests don't collide.

By default fakeredis simulates network latency to help you discover race-conditions when testing multi-client setups. Network latency can be disabled using the .fast option:

var client = require("fakeredis").createClient(port, host, { fast : true });

One key difference is that the output of some commands, such as SMEMBERS, HKEYS, HVALS, comes out sorted lexicographically to provide for simpler testing. This means that some tests that make use of undocumented Redis behaviours such as the chronological order of retrieval for members in a set may fail when attempted with fakeredis. To solve this, whenever there is no documented sort order for a given Redis command's multi-bulk reply, sort the output before asserting equality to ensure your tests run everywhere.

Another major difference is that commands that accept modifier parameters, such as SORT key [BY pattern] [LIMIT offset count] [GET pattern [GET pattern ...]] [ASC|DESC] [ALPHA] [STORE destination] currently only accept these parameters in the order that is stated in the documentation. For example, in Redis it appears to be perfectly legitimate to have SORT myset ALPHA LIMIT 0 5, but in fakeredis this will currently return a syntax error.

I'm totally open to discussion on both points.

Fakeredis is still mostly stuck in the Redis 2.4 era.

All Redis 2.4 string, list, hash, set and sorted set commands, most keyspace commands, and some connection and server commands. Pubsub, transactions with optimistic locking are also fully implemented.

List of available commands:

Keyspace:

DBSIZE EXISTS EXPIRE EXPIREAT FLUSHDB KEYS PERSIST DEL RANDOMKEY RENAME RENAMENX SORT TTL TYPE 

Strings:

APPEND BITCOUNT DECR DECRBY GET GETBIT GETRANGE GETSET INCR INCRBY MGET MSET MSETNX SET SETBIT SETEX SETNX SETRANGE 

Hashes:

HDEL HEXISTS HGET HGETALL HINCRBY HKEYS HLEN HMGET HMSET HSET HSETNX HVALS 

Lists:

BLPOP BRPOP BRPOPLPUSH LINDEX LINSERT LLEN LPOP LPUSH LPUSHX LRANGE LREM LSET LTRIM RPOP RPOPLPUSH RPUSH RPUSHX 

Sets:

SADD SCARD SDIFF SDIFFSTORE SINTER SINTERSTORE SISMEMBER SMEMBERS SMOVE SPOP SRANDMEMBER SREM STRLEN SUNION SUNIONSTORE 

Sorted Sets:

ZADD ZCARD ZCOUNT ZINCRBY ZINTERSTORE ZRANGE ZRANGEBYSCORE ZRANK ZREM ZREMRANGEBYRANK ZREMRANGEBYSCORE ZREVRANGE ZREVRANGEBYSCORE ZREVRANK ZSCORE ZUNIONSTORE 

Pub/Sub:

PSUBSCRIBE PUBLISH PUNSUBSCRIBE SUBSCRIBE UNSUBSCRIBE 

Transactions:

DISCARD EXEC MULTI UNWATCH WATCH 

Connection and Server:

ECHO PING QUIT SELECT 

These do nothing but return OK:

AUTH BGREWRITEAOF BGSAVE SAVE 

Most notably, there's no support for Lua scripting and MONITOR is still missing.

None of the ready, connect, error, end, drain and idle client events are currently implemented.

List of missing commands (will throw upon attempt to use):

Connection and Server:

CONFIG GET CONFIG SET CONFIG RESETSTAT DEBUG OBJECT DEBUG SEGFAULT FLUSHALL INFO LASTSAVE MONITOR MOVE OBJECT SHUTDOWN SLAVEOF SYNC 

MIT.