feat: add integration and setup tests and complete code review fixes

README.md

@@ -61,6 +61,10 @@ The following environment variables can be configured in your `.env` file:
 | `PDF_OUTPUT_DIR`            | `tickets`                | Directory for generated PDF tickets      |
 | `PDF_CLEANUP_MAX_AGE_HOURS` | `24`                     | Maximum age for PDF cleanup              |
 | `TEST_URL`                  | `http://localhost:3049`  | Base URL for load testing                |
+| `ALLOWED_ORIGINS`           | `localhost:3000,3049`    | CORS allowed origins                     |
+| `RATE_LIMIT_ENABLED`        | `true`                   | Enable rate limiting                     |
+| `SECURITY_HEADERS_ENABLED`  | `true`                   | Enable security headers                  |
+| `REDIS_SCAN_BATCH_SIZE`     | `100`                    | Redis SCAN batch size for performance    |
 
 ### Quick Start
 
@@ -169,6 +173,26 @@ node tests/load-test.js --event 2 --connections 1000 --duration 10
 # Test fallback store functionality
 npm run test:fallback
 
+# Test security features
+npm run test:security
+
+# Run comprehensive test suite
+npm test
+
+# Run specific test categories
+npm run test:unit          # Unit tests only
+npm run test:integration   # Integration tests only
+npm run test:performance   # Performance tests only
+
+# Run critical duplicate prevention tests
+npm run test:duplicate-prevention
+
+# Run with coverage report
+npm run test:coverage
+
+# Run tests in watch mode (development)
+npm run test:watch
+
 ### Monitoring & Metrics
 
 #### Application Metrics
@@ -226,6 +250,88 @@ docker-compose up -d --build
 - **Logging & Metrics:** Proper logging of operations and a functional metrics endpoint suitable for Prometheus scraping.
 - **Design Rationale:** The design document (`design.md`) should clearly articulate your architectural decisions, potential bottlenecks, and design solutions.
 
+## Testing Suite
+
+The project includes a comprehensive testing framework to ensure reliability and prevent critical issues:
+
+### Test Categories
+
+- **Unit Tests** (`tests/unit/`): Test individual components in isolation
+- **Integration Tests** (`tests/integration/`): Test component interactions and API endpoints
+- **Performance Tests** (`tests/performance/`): Verify system behavior under high load
+
+### Critical Test Coverage
+
+- **Duplicate Prevention**: Automated verification that no ticket is sold more than once
+- **High Concurrency**: Tests with 100+ concurrent requests to ensure data integrity
+- **Fallback Mode**: Comprehensive testing of Redis failure scenarios
+- **API Endpoints**: Full coverage of all REST endpoints with edge case handling
+- **Security Features**: Validation of rate limiting, input validation, and security headers
+
+### Running Tests
+
+```bash
+# Run all tests
+npm test
+
+# Run specific test categories
+npm run test:unit          # Unit tests only
+npm run test:integration   # Integration tests only
+npm run test:performance   # Performance tests only
+
+# Run critical duplicate prevention tests
+npm run test:duplicate-prevention
+
+# Generate coverage report
+npm run test:coverage
+
+# Run tests in watch mode (development)
+npm run test:watch
+
+# Use the test runner script for easier test execution
+node run-tests.js all           # Run all tests
+node run-tests.js validate      # Run core requirement validation
+node run-tests.js duplicate     # Run duplicate prevention tests only
+node run-tests.js quick         # Run quick test suite
+```
+
+### Test Requirements
+
+- **No Duplicate Tickets**: Core requirement verified by automated tests
+- **High Concurrency**: System tested with 100+ concurrent requests
+- **Data Consistency**: Redis and fallback store synchronization verified
+- **Performance**: Response times and memory usage monitored under load
+- **Security**: All security features validated with comprehensive tests
+
+## Security Features
+
+The system includes comprehensive security measures to protect against common threats:
+
+### Rate Limiting
+
+- **General API**: 100 requests per 15 minutes
+- **Purchase Endpoints**: 10 requests per minute
+- **Admin Endpoints**: 20 requests per 5 minutes
+
+### Input Validation
+
+- **Event IDs**: Must be positive integers
+- **Purchase IDs**: Must be valid UUIDs
+- **Request Parameters**: Validated and sanitized
+
+### Security Headers
+
+- **Content Security Policy**: Prevents XSS attacks
+- **HSTS**: Enforces HTTPS connections
+- **XSS Protection**: Additional XSS prevention
+- **Frame Guard**: Prevents clickjacking
+
+### Request Security
+
+- **Size Limits**: Maximum 1MB request size
+- **CORS Protection**: Configurable allowed origins
+- **Security Logging**: Suspicious request monitoring
+
 ## Troubleshooting
 
 ### Common Issues