feat (resp): Add integration tests for resp

[geofmureithi]

Integration Testing for RESP Server

Overview

We need comprehensive integration tests for the RESP protocol server implementation to ensure all protocol commands work correctly in real-world scenarios with actual TCP connections.

Background

Currently, the RESP server has unit tests, but we lack integration tests that validate the full client-server interaction over TCP. Integration tests will help us catch issues related to:

• Network communication and connection handling
• Protocol serialization/deserialization in real scenarios
• State management across multiple requests
• Concurrent client handling
• Edge cases and error conditions

Goals

Create a robust integration test suite that:

1. Tests all RESP protocol commands end-to-end
2. Validates multi-client scenarios
3. Ensures proper connection lifecycle management
4. Verifies error handling and edge cases
5. Tests worker state transitions (Consumer → Quiet → Terminating)

Test Scenarios to Cover

Basic Protocol Flow

• Server startup and greeting (HI command)
• Client authentication (with and without password)
• Producer workflow: HELLO → PUSH → END
• Consumer workflow: HELLO → FETCH → ACK → END
• Consumer failure workflow: HELLO → FETCH → FAIL → END

Job Lifecycle

• Push job and verify it's queued
• Fetch job from default queue
• Fetch job from specific named queues
• Fetch with multiple queue priority
• ACK job and verify removal
• FAIL job and verify retry scheduling
• Job with retry limit exhaustion (moves to dead)
• Scheduled jobs (with at field)
• Job reservation timeout and re-queueing

Worker Management

• Worker registration via HELLO
• Worker heartbeat (BEAT) responses
• Worker state transitions (quiet, terminate)
• Multiple workers on same queue
• Worker disconnection cleanup

Concurrency & Race Conditions

• Multiple producers pushing jobs simultaneously
• Multiple consumers fetching from same queue
• Job reservation conflicts
• Concurrent ACK/FAIL operations
• Worker registration race conditions

Error Handling

• Invalid JSON in commands
• Missing required fields
• Commands in wrong state (e.g., FETCH before HELLO)
• Invalid job IDs in ACK/FAIL
• Protocol version mismatch
• Authentication failures
• Malformed RESP responses

Administrative Commands

• INFO command and response parsing
• FLUSH command clears all jobs
• Graceful connection termination with END

Edge Cases

• Empty queue fetch (should return null bulk string)
• Job with no retry (retry: 0)
• Job with infinite retry (retry: -1)
• Very long job arguments
• Unicode/special characters in job data
• Rapid connect/disconnect cycles
• Server under load (many concurrent connections)