[FEATURE] JS interoperablity test in nodejs check socketio client v1-v4 (Engine. IO v2 & v3)

[sanjomo]

Summary

Expand the existing Node.js interoperability test suite to validate SocketIO4j compatibility with Socket.IO JavaScript clients from v1 through v4.

Motivation

Node.js interoperability tests provide fast protocol-level validation without requiring browser execution while ensuring compatibility across multiple Socket.IO protocol generations.

These tests serve as a fast regression suite for protocol changes.

Coverage

Socket.IO Client Versions

• v1.x (Engine.IO v2)
• v2.x (Engine.IO v3)
• v3.x (Engine.IO v4)
• v4.x (Engine.IO v4)

Transport Modes

• HTTP Polling
• WebSocket
• Transport upgrades (where applicable)

Features

• Connection lifecycle
• Event emission
• ACK callbacks
• Binary attachments
• Mixed payloads
• Namespace support
• Error handling
• Authentication
• Multiple concurrent clients

Validation

Tests verify:

• Protocol interoperability
• Packet encoding/decoding
• Binary attachment handling
• ACK semantics
• Namespace routing
• Connection establishment
• Disconnect handling
• Engine.IO compatibility

Benefits

• Fast interoperability regression tests
• Protocol compatibility verification
• Backward compatibility across Socket.IO client generations
• Complements browser interoperability tests