test: Redis driver conformance + benchmark vs go-redis

[FumingPower3925]

Summary

Comprehensive conformance tests and performance benchmarks for the celeris Redis driver. Tests validate correctness against a real Redis instance. Benchmarks compare against go-redis (the most popular Go Redis client).

Conformance Tests

Connection

• AUTH with password
• SELECT database
• Connection pooling behavior
• Reconnection after connection drop

Commands

• Strings: GET, SET, SETNX, DEL, EXISTS, INCR, DECR, EXPIRE, TTL, PERSIST
• Hashes: HGET, HSET, HDEL, HGETALL, HEXISTS, HKEYS, HVALS
• Lists: LPUSH, RPUSH, LPOP, RPOP, LRANGE, LLEN
• Sets: SADD, SREM, SMEMBERS, SISMEMBER, SCARD, SUNION, SINTER
• Sorted Sets: ZADD, ZRANGE, ZRANGEBYSCORE, ZREM, ZSCORE, ZCARD
• Keys: TYPE, RENAME, RANDOMKEY, SCAN
• NULL/nil responses for missing keys
• Error responses for wrong-type operations

Pipeline

• Batch 100+ commands
• Correct response ordering
• Error in middle of pipeline doesn't affect other commands
• Nested pipeline (pipeline within pipeline)

Pub/Sub

• Subscribe/unsubscribe single channel
• Pattern subscribe
• Message delivery latency
• Reconnection with resubscription
• Multiple subscribers on same channel

Pool

• Worker affinity routing
• Overflow to shared pool
• MaxOpen enforcement
• Idle connection cleanup
• Concurrent access from multiple goroutines

Benchmarks

vs go-redis Comparison

BenchmarkGet/celeris
BenchmarkGet/go-redis
BenchmarkSet/celeris
BenchmarkSet/go-redis
BenchmarkPipeline100/celeris
BenchmarkPipeline100/go-redis
BenchmarkConcurrent/celeris
BenchmarkConcurrent/go-redis
BenchmarkPoolGetRelease/celeris
BenchmarkPoolGetRelease/go-redis

Metrics

• Commands per second
• Latency (p50, p99)
• Memory allocations per command
• Pipeline throughput (commands/sec)

Acceptance Criteria

• All conformance tests pass against Redis 7+
• Tests run in CI with Redis container
• Benchmark suite comparing against go-redis
• Zero-alloc on GET/SET hot path (verified by benchmarks)
• Pool tests validate worker affinity
• Pub/Sub tests verify message delivery

Dependencies

• Depends on 133 (Redis client API)
• Depends on 136 (Redis connection pool)