Redis
Distributed caches introduce consistency problems that single-node caches don't have. When your cache is spread across multiple Redis nodes—or when multiple application instances share a cache—the same key might return different values depending on which node serves the request. Testing these properties requires deliberate setup.
Redis
Redis Pub/Sub and Redis Streams are fundamentally different messaging primitives, and each requires distinct testing approaches. Pub/Sub is ephemeral—messages are lost if no subscriber is connected. Streams are persistent—messages are stored until explicitly deleted. This guide shows how to test both reliably. Redis Pub/Sub Testing
Redis
Testing code that depends on Redis presents a fundamental choice: simulate Redis in-process with a mock library, or spin up a real Redis instance via Testcontainers. Both approaches have distinct trade-offs that affect test speed, reliability, and the bugs you catch. This guide walks through both options in
Redis
Redis Cluster is the native horizontal scaling solution for Redis. It partitions data across multiple nodes using consistent hashing (16384 slots), with each node responsible for a subset. When a primary fails, a replica is promoted. This guide covers how to test cluster behavior—slot assignment, redirects, failover, and reconnection—
Redis
Phil Karlton famously said there are only two hard things in computer science: cache invalidation and naming things. Testing cache invalidation is hard for different reasons—the behavior is time-dependent, state-dependent, and often involves distributed components that are difficult to simulate in isolation. This guide covers the major
Testing
BullMQ's advanced features — flow producers, delayed jobs, rate limiters, and job groups — enable sophisticated background processing patterns.
Testing
Redis Streams differ from simple pub/sub — they persist messages and track consumer group acknowledgments via the Pending Entries List (PEL). Testing consumer groups means verifying XACK behavior, idle consumer claim logic, and re-delivery after consumer failure. Testcontainers provides a real Redis instance; Python's redis-py gives
Database Testing
Redis powers some of the fastest parts of modern applications — caches, session stores, queues, leaderboards.