Add comprehensive testing for proxy package

[blink-so-v1]

This PR adds comprehensive testing for the proxy package, improving reliability and maintainability.

📊 Coverage Improvement

Adds full test coverage for the proxy package including:

🧪 Key Improvements

Configuration Validation

• ✅ Valid configurations with all components
• ✅ Zero ports (dynamic allocation)
• ✅ Nil component handling
• ✅ Invalid configuration detection (negative ports)

Server Lifecycle Testing

• ✅ Server creation with various configurations
• ✅ Start/stop functionality with proper timeout handling
• ✅ Thread-safe server operations with mutex protection
• ✅ Graceful shutdown on context cancellation

Request Handling

• ✅ HTTP request proxying for allowed requests
• ✅ HTTPS CONNECT method handling
• ✅ Blocked request responses with proper status codes
• ✅ Request auditing integration
• ✅ Rule engine evaluation

Integration Testing

• ✅ End-to-end proxy functionality
• ✅ Multiple HTTP methods (GET, POST, PUT, DELETE, HEAD)
• ✅ Real target server communication
• ✅ Audit trail verification

Error Handling & Edge Cases

• ✅ Nil component graceful handling
• ✅ Network error scenarios
• ✅ Invalid request processing
• ✅ Blocked response formatting

🔧 Technical Excellence

Thread Safety Improvements

• Added sync.Mutex to Server struct for concurrent access protection
• Proper locking around server creation and access in Start method
• Thread-safe server reference handling in goroutines

Mock Implementations

• Complete mockRuleEngine implementing rules.Evaluator
• Full mockAuditor implementing audit.Auditor
• Configurable test scenarios (allow/block rules)

Test Quality

• Table-driven tests for comprehensive coverage
• Integration tests with real HTTP servers
• Benchmark tests for performance measurement
• Clear error messages and debugging support

Performance Testing

• Benchmarks for server creation
• Benchmarks for allowed vs blocked request handling
• Performance optimization insights

🚀 Benefits

1. Reliability: Proxy functionality is thoroughly tested
2. Thread Safety: Concurrent operations properly protected
3. Maintainability: Clear test structure enables safe refactoring
4. Documentation: Tests serve as executable proxy usage examples
5. Quality Assurance: Edge cases and error conditions fully covered

All tests pass successfully with appropriate handling of system constraints and network operations.

Co-authored-by: f0ssel [email protected]