Wraps Redis cache testing: EXPIRE / PEXPIRE / TTL verification (Redis 7+ NX/XX/GT/LT flags), cache-aside write-then-invalidate (write source → DEL key → assert fresh read), eviction under memory pressure (maxmemory + allkeys-lru), pub/sub invalidation across nodes, and tenant key-namespacing. Use when Redis is the app's primary cache. For the CDN/browser HTTP tier use cdn-cache-purge-tests; a runnable test, not the cache-coherence-patterns-reference catalog (which owns the stampede + stale-while-revalidate references).