FakeStore MCP

# Testing Documentation ## Overview This project has a comprehensive testing setup with both unit tests and end-to-end (E2E) tests for the MCP server functionality. ## Test Structure ### Unit Tests (`*.test.ts`) - **Location**: `src/app/api/mcp/route.test.ts` - **Purpose**: Test MCP server handlers with mocked fetch calls - **Setup**: Uses `jest-fetch-mock` to mock external API calls - **Coverage**: - Tool listing functionality - Tool execution with mocked responses - Cart operations flow with authentication - Error handling scenarios ### E2E Tests (`*.e2e.test.ts`) - **Location**: `src/app/api/mcp/route.e2e.test.ts` - **Purpose**: Test MCP server with real FakeStore API calls - **Setup**: Uses `undici` fetch for real network requests - **Coverage**: - Real product data retrieval - Category listing - Product filtering - Tool schema validation ## Running Tests ### All Tests ```bash npm test ``` ### Unit Tests Only ```bash npm test -- --selectProjects=unit ``` ### E2E Tests Only ```bash npm test -- --selectProjects=e2e ``` ### Specific Test Pattern ```bash npm test -- --testNamePattern="cart operations" ``` ## Test Configuration ### Jest Configuration (`jest.config.ts`) - Uses `ts-jest` with ESM support - Separate projects for unit and E2E tests - Different setup files for each test type ### Setup Files - **`jest.setup.ts`**: Unit test setup with fetch mocking - **`jest.e2e.setup.ts`**: E2E test setup with real fetch ## Key Features Tested ### MCP Server Functionality - ✅ Tool registration and listing - ✅ Tool execution with proper request/response format - ✅ Session management - ✅ Error handling and validation ### FakeStore API Integration - ✅ Product retrieval (single and multiple) - ✅ Category listing - ✅ Product filtering by category - ✅ Authentication flow - ✅ Cart operations (add, remove, get, clear) ### API Response Validation - ✅ JSON-RPC 2.0 format compliance - ✅ MCP protocol adherence - ✅ Proper error responses - ✅ Content structure validation ## Test Data ### Demo Users (from FakeStore API) ```typescript const DEMO_USERS = [ { username: 'johnd', password: 'm38rmF$', name: 'John Doe', email: 'john@gmail.com' }, { username: 'mor_2314', password: '83r5^_', name: 'David Morrison', email: 'morrison@gmail.com' }, { username: 'kevinryan', password: 'kev02937@', name: 'Kevin Ryan', email: 'kevin@gmail.com' }, { username: 'donero', password: 'ewedon', name: 'Don Romer', email: 'don@gmail.com' }, ] ``` ## Dependencies ### Test Dependencies - `jest` - Testing framework - `ts-jest` - TypeScript support for Jest - `@types/jest` - TypeScript definitions - `jest-environment-node` - Node.js test environment - `jest-fetch-mock` - Fetch mocking for unit tests - `undici` - Real fetch implementation for E2E tests ## Best Practices 1. **Separation of Concerns**: Unit tests use mocks, E2E tests use real APIs 2. **Comprehensive Coverage**: Both happy path and error scenarios 3. **Real Data**: E2E tests validate against actual FakeStore API responses 4. **Type Safety**: Full TypeScript support in all test files 5. **Fast Feedback**: Unit tests run quickly with mocks 6. **Integration Validation**: E2E tests ensure real-world functionality ## Troubleshooting ### Common Issues - **Fetch Errors**: Ensure `undici` is installed for E2E tests - **ESM Issues**: Check `jest.config.ts` transform settings - **Type Errors**: Verify TypeScript configuration is correct - **Network Issues**: E2E tests require internet connection ### Debug Commands ```bash # Run tests with verbose output npm test -- --verbose # Run specific test file npm test -- src/app/api/mcp/route.test.ts # Run tests in watch mode npm test -- --watch ```