Analytical MCP Server

# Enhanced Error Handling Testing Documentation ## Overview This document describes the comprehensive testing approach for the enhanced error handling system implemented in the Analytical MCP Server. The testing suite ensures reliability, backward compatibility, and proper error recovery across all analytical tools. ## Testing Architecture ### 1. Core Error Infrastructure Tests **File**: `src/utils/__tests__/enhanced-errors.test.ts` **Coverage**: - ✅ **ErrorCodes enum** - All 20 standardized error codes (ERR_1001-ERR_5003) - ✅ **Error Recovery Strategies** - Retry configurations with exponential backoff - ✅ **Enhanced Error Classes** - AnalyticalError, ValidationError, APIError, etc. - ✅ **Helper Functions** - createValidationError, createAPIError, isRecoverable - ✅ **Retry Logic** - executeWithRetry with backoff and timeout handling - ✅ **withErrorHandling Wrapper** - Tool wrapping with automatic error transformation **Key Test Categories**: - Error code organization and consistency - Recovery strategy configuration validation - Error class inheritance and instanceof checks - Context preservation and enhancement - Retry logic with timer advancement - Generic error transformation into AnalyticalErrors ### 2. Legacy Compatibility Tests **File**: `src/utils/__tests__/errors.test.ts` (Updated) **Coverage**: - ✅ **Backward Compatibility** - Legacy error classes still work - ✅ **Type Guards** - isErrorType function works with both legacy and enhanced errors - ✅ **API Consistency** - Existing tool integrations remain functional ### 3. Tool Integration Tests **File**: `src/utils/__tests__/tool-integration.test.ts` **Coverage**: - ✅ **Real Tool Simulation** - Complex analytical tools with multiple error scenarios - ✅ **Retry Behavior** - API rate limiting with automatic retry and backoff - ✅ **Error Categorization** - Generic errors transformed into appropriate AnalyticalError types - ✅ **Context Preservation** - Tool names, parameters, and debugging information - ✅ **Mixed Error Scenarios** - Tools throwing different error types in sequence - ✅ **Large Argument Handling** - Graceful handling of tools with many parameters **Sample Tools Tested**: - `analyzeDataset` - Data validation and processing errors - `apiTool` - Rate limiting and timeout handling - `complexAnalyticalTool` - Multi-step validation and processing ### 4. Performance Monitoring Tests **File**: `src/utils/__tests__/performance-monitoring.test.ts` **Coverage**: - ✅ **Metrics Collection** - Execution time, memory usage, cache hit rates - ✅ **Health Status Monitoring** - Healthy/Warning/Critical status based on performance - ✅ **Error Rate Tracking** - Success/failure ratios and trends - ✅ **Performance Degradation Detection** - Trend analysis over time - ✅ **Memory Usage Tracking** - Memory-intensive operation monitoring **Mock ToolMetrics Interface**: ```typescript interface ToolMetrics { executionTime: number; memoryUsage: number; cacheHitRate: number; errorCount?: number; retryCount?: number; } ``` ### 5. Migration Example Tests **File**: `src/utils/__tests__/example-tool-migration.test.ts` **Coverage**: - ✅ **Before/After Comparison** - Original vs migrated tool behavior - ✅ **Enhanced Error Context** - Rich debugging information - ✅ **Functionality Preservation** - Same results with better error handling - ✅ **Structured Error Information** - Consistent error formats across tools ## Error Code Standards ### Validation Errors (1xxx) - `ERR_1001` - Invalid Input - `ERR_1002` - Missing Required Parameter - `ERR_1003` - Invalid Data Format - `ERR_1004` - Invalid Parameter Type - `ERR_1005` - Parameter Out of Range ### API Errors (2xxx) - `ERR_2001` - API Rate Limit - `ERR_2002` - API Authentication Failed - `ERR_2003` - API Timeout - `ERR_2004` - API Service Unavailable - `ERR_2005` - API Invalid Response ### Processing Errors (3xxx) - `ERR_3001` - Calculation Failed - `ERR_3002` - Memory Limit - `ERR_3003` - Timeout - `ERR_3004` - Insufficient Data - `ERR_3005` - Algorithm Convergence Failed ### Configuration Errors (4xxx) - `ERR_4001` - Missing Configuration - `ERR_4002` - Invalid Configuration - `ERR_4003` - Configuration Load Failed ### Tool Execution Errors (5xxx) - `ERR_5001` - Tool Not Found - `ERR_5002` - Tool Execution Failed - `ERR_5003` - Tool Dependency Missing ## Recovery Strategies ### Automatic Retry Configuration ```typescript const errorRecoveryStrategies = { [ErrorCodes.API_RATE_LIMIT]: { retry: { times: 3, delay: 1000, backoff: 2 }, cache: true }, [ErrorCodes.API_TIMEOUT]: { retry: { times: 2, delay: 500, backoff: 1.5 } }, [ErrorCodes.API_SERVICE_UNAVAILABLE]: { retry: { times: 3, delay: 2000, backoff: 2 } } }; ``` ## Tool Migration Pattern ### Before (Legacy) ```typescript export async function analyzeDataset(data: any[], type: string) { if (!data || data.length === 0) { throw new Error('Data array is required'); } // ... processing } ``` ### After (Enhanced) ```typescript async function analyzeDatasetInternal(data: any[], type: string) { if (!data || data.length === 0) { throw createValidationError( 'Data array is required and must not be empty', { data, type }, 'analyze_dataset' ); } // ... processing } export const analyzeDataset = withErrorHandling( 'analyze_dataset', analyzeDatasetInternal ); ``` ## Test Execution ### Running All Error Tests ```bash npm test -- --testPathPattern="errors" ``` ### Running Specific Test Suites ```bash # Enhanced error infrastructure npm test src/utils/__tests__/enhanced-errors.test.ts # Tool integration tests npm test src/utils/__tests__/tool-integration.test.ts # Performance monitoring npm test src/utils/__tests__/performance-monitoring.test.ts # Migration examples npm test src/utils/__tests__/example-tool-migration.test.ts ``` ### Test Coverage Expectations - **Error Infrastructure**: 100% coverage of error classes and helper functions - **Retry Logic**: Complete coverage of exponential backoff and timeout scenarios - **Tool Integration**: Coverage of realistic error scenarios across tool types - **Performance Monitoring**: Coverage of metrics collection and health status logic ## Benefits Validated by Tests ### 1. Debugging Enhancement - **Clear Error Codes**: ERR_1001-ERR_5003 for easy categorization - **Rich Context**: Tool names, parameters, and debugging information - **Structured Errors**: Consistent format across all analytical tools ### 2. Reliability Improvement - **Automatic Recovery**: Rate limiting and timeout retry with exponential backoff - **Error Context Preservation**: Full debugging information maintained through error chains - **Graceful Degradation**: Non-recoverable errors fail fast, recoverable errors retry ### 3. Monitoring & Observability - **Performance Metrics**: Execution time, memory usage, cache hit rates - **Health Status**: Automated healthy/warning/critical status based on metrics - **Trend Analysis**: Performance degradation detection over time ### 4. Developer Experience - **Backward Compatibility**: Existing tools continue to work without changes - **Migration Path**: Clear pattern for enhancing existing tools - **Type Safety**: Full TypeScript support with proper error typing ## Future Test Enhancements ### Additional Test Scenarios - **Load Testing**: High-concurrency error handling behavior - **Memory Leak Detection**: Long-running retry scenarios - **Network Simulation**: Realistic API failure and recovery patterns - **Tool Chaining**: Error propagation through analytical tool pipelines ### Monitoring Integration - **Real-time Dashboards**: Performance metrics visualization - **Alert Thresholds**: Automated notifications for critical error rates - **Trend Analytics**: Machine learning-based performance anomaly detection This comprehensive testing approach ensures the enhanced error handling system provides robust, reliable, and maintainable error management across all analytical tools while maintaining full backward compatibility with existing implementations.