In-Memory Driver

MemoryRedisAdapter extends the same BaseRedisDriver as the production adapters, implementing its five primitives (doConnect, doDisconnect, executeCommand, createPipeline, createMulti) over an in-memory keyspace. The other ~180 driver methods are inherited unchanged.

Supported commands

Group	Commands
Strings	GET, SET (EX/PX/NX/XX/GET), SETEX, SETNX, APPEND, STRLEN, INCR, INCRBY, DECR, DECRBY, MGET, MSET
Keys / TTL	DEL, UNLINK, EXISTS, EXPIRE, PEXPIRE, EXPIREAT, PEXPIREAT, PERSIST, TTL, PTTL, TYPE, KEYS, SCAN
Hashes	HSET, HMSET, HGET, HMGET, HGETALL, HDEL, HEXISTS, HLEN, HKEYS, HVALS, HINCRBY
Sets	SADD, SREM, SMEMBERS, SISMEMBER, SCARD
Sorted sets	ZADD, ZREM, ZCARD, ZSCORE, ZRANGE, ZRANGEBYSCORE, ZREMRANGEBYSCORE, ZCOUNT
Lists	LPUSH, RPUSH, LPOP, RPOP, LLEN, LRANGE, LINDEX, LREM
Streams	XADD (NOMKSTREAM/MAXLEN/MINID), XLEN, XRANGE, XREVRANGE, XDEL, XTRIM, XINFO STREAM, XGROUP (CREATE/DESTROY/SETID/DELCONSUMER), XREADGROUP, XREAD, XACK, XPENDING, XCLAIM
Scripting	EVAL, EVALSHA, SCRIPT LOAD
Server	PING, DBSIZE, FLUSHDB, FLUSHALL

This set covers everything the cache, locks, rate-limit, idempotency, and streams plugins use. TTL is enforced with lazy expiry: an expired key is evicted the next time it is read.

Streams and consumer groups

Streams are modelled with real consumer-group semantics: monotonic <ms>-<seq> ids, per-group delivery cursors, per-consumer pending-entries lists (PEL), delivery counts, and idle-time tracking. So XREADGROUP ... > delivers only never-seen entries and records them in the PEL; XACK clears them; XPENDING and XCLAIM let another consumer reclaim idle messages — exactly what the Streams plugin's consumer loop and auto-claim rely on.

The in-memory driver never truly blocks. A blocking XREADGROUP/XREAD that finds nothing returns null after a short delay (instead of waiting the full BLOCK timeout), which keeps a background consumer poll loop responsive without starving the event loop.

Lua scripting

The plugins rely on Lua scripts for atomicity (e.g. token-bucket rate limiting, owner-checked lock release). The in-memory driver runs them on a small in-house interpreter — no third-party engine. redis.call(...) re-enters the same executor, so a script sees a consistent, single-threaded view, exactly like Redis.

The interpreter supports the bounded subset the project's scripts use:

• KEYS / ARGV, local variables, assignment, and table indexing
• redis.call / redis.pcall (over the supported command set above)
• if / elseif / else, numeric for loops (with optional step)
• arithmetic (+ - * / %), comparison, logical and / or / not, concat ..
• # length, tonumber, tostring, math.floor / ceil / abs / min / max
• array + hashmap tables (HGETALL is flattened to a [field, value, …] array, as on Redis)

Anything outside this subset (e.g. string.*, cjson, while, closures) raises a LuaExecutionError rather than returning a silently wrong result.

Limitations

What it intentionally does not simulate

• No real blocking — BLOCK on XREADGROUP/XREAD returns promptly instead of waiting; delivery is still correct, only the timing differs.
• Pub/Sub is a process-wide bus — PUBLISH/SUBSCRIBE/PSUBSCRIBE work across all in-memory connections inside one test process (single-node semantics; no sharded Pub/Sub, no cross-process delivery).
• Single keyspace — no multi-database (SELECT) or cross-slot cluster semantics; behavior matches a single standalone Redis, so a missing hash-tag passes here but can fail on a real cluster.
• Not for load testing — it is a correctness tool for unit tests, not a performance simulator.
• Unsupported commands fail loudly — calling a command the driver does not implement throws MemoryDriverError, surfacing gaps instead of hiding them.

For cluster routing, cross-process Pub/Sub, failover, or performance, test against a real Redis — see When to Use It.

Direct use

You can construct the adapter directly when you need a driver without Nest:

import { MemoryRedisAdapter } from '@nestjs-redisx/testing';

const driver = new MemoryRedisAdapter({ type: 'single', host: 'x', port: 1 });
await driver.connect();

await driver.set('k', 'v');
await driver.get('k'); // 'v'