OpenAPI to MCP Server

import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'; import fs from 'fs/promises'; import path from 'path'; import { testConfig } from '../fixtures/test-config'; import { mapOpenApiToMcpTools } from '../../src/mcpMapper'; import { createTestApiCallDetails } from '../utils/testTypes'; // Import the mocked API client instead of the real one import { executeApiCall, mockApiError, resetApiMock } from '../mocks/apiClient.mock'; // Store original environment variables const originalEnv = { ...process.env }; // Mock the API client module jest.mock('../../src/apiClient', () => ({ executeApiCall })); describe('OpenAPI to MCP Integration Tests', () => { let openApiSpec: any; beforeAll(async () => { // Load the test OpenAPI spec directly from the fixture file const content = await fs.readFile(path.resolve(process.cwd(), testConfig.openApiFile), 'utf-8'); openApiSpec = JSON.parse(content); }); beforeEach(() => { // Reset mocks between tests jest.clearAllMocks(); resetApiMock(); // Reset environment variables to original state process.env = { ...originalEnv }; }); afterAll(() => { // Restore environment process.env = originalEnv; }); describe('OpenAPI Parsing', () => { it('should contain expected paths and operations', () => { // Test the OpenAPI spec structure directly expect(openApiSpec).toBeDefined(); expect(openApiSpec.openapi).toBe('3.0.0'); expect(openApiSpec.info.title).toBe('Petstore API'); // Verify paths expect(openApiSpec.paths).toBeDefined(); expect(openApiSpec.paths["/pets"]).toBeDefined(); expect(openApiSpec.paths["/pets/{petId}"]).toBeDefined(); // Verify operations expect(openApiSpec.paths["/pets"].get).toBeDefined(); expect(openApiSpec.paths["/pets"].get.operationId).toBe('listPets'); expect(openApiSpec.paths["/pets"].post).toBeDefined(); expect(openApiSpec.paths["/pets"].post.operationId).toBe('createPet'); expect(openApiSpec.paths["/pets/{petId}"].get).toBeDefined(); expect(openApiSpec.paths["/pets/{petId}"].get.operationId).toBe('getPetById'); // Verify schemas expect(openApiSpec.components.schemas.Pet).toBeDefined(); expect(openApiSpec.components.schemas.NewPet).toBeDefined(); expect(openApiSpec.components.schemas.Pets).toBeDefined(); }); }); describe('MCP Mapper', () => { it('should map OpenAPI spec to MCP tools', () => { // Test the mapping function const mappedTools = mapOpenApiToMcpTools(openApiSpec); // Verify the tools were mapped correctly expect(mappedTools).toBeDefined(); expect(Array.isArray(mappedTools)).toBe(true); expect(mappedTools.length).toBe(3); // 3 operations in our test spec // Check tool names const toolNames = mappedTools.map(tool => tool.mcpToolDefinition.name); expect(toolNames).toContain('listPets'); expect(toolNames).toContain('getPetById'); expect(toolNames).toContain('createPet'); // Verify tool structure for one tool const listPetsTool = mappedTools.find(tool => tool.mcpToolDefinition.name === 'listPets'); expect(listPetsTool).toBeDefined(); expect(listPetsTool?.mcpToolDefinition.description).toBeDefined(); expect(listPetsTool?.mcpToolDefinition.inputSchema).toBeDefined(); expect(listPetsTool?.apiCallDetails.method).toBe('GET'); }); it('should respect operation filtering via environment variables', () => { // Set the correct environment variables that the config actually uses process.env.MCP_WHITELIST_OPERATIONS = 'listPets'; process.env.MCP_BLACKLIST_OPERATIONS = ''; // Re-require the config to force it to read the updated environment variables jest.resetModules(); jest.doMock('../../src/config', () => ({ config: { filter: { whitelist: ['listPets'], blacklist: [] } } })); // Get a fresh instance of the function with the mocked config const { mapOpenApiToMcpTools } = require('../../src/mcpMapper'); // Test filtering const filteredTools = mapOpenApiToMcpTools(openApiSpec); // Should now only have listPets expect(filteredTools.length).toBe(1); expect(filteredTools[0].mcpToolDefinition.name).toBe('listPets'); // Reset mocks to not affect other tests jest.dontMock('../../src/config'); }); }); describe('API Client', () => { it('should correctly execute API calls', async () => { // Set up test data const mockResponse = { id: 1, name: 'Rex', tag: 'dog' }; executeApiCall.mockImplementationOnce(async () => ({ success: true, statusCode: 200, data: mockResponse, headers: new Headers({ 'Content-Type': 'application/json' }) })); // Create API call details const apiCallDetails = createTestApiCallDetails({ method: 'GET', pathTemplate: '/pets/{petId}', serverUrl: 'http://example.com/api' }); // Execute the API call const result = await executeApiCall(apiCallDetails, { petId: '1' }); // Verify the result expect(result).toBeDefined(); expect(result.success).toBe(true); expect(result.statusCode).toBe(200); expect(result.data).toEqual(mockResponse); // Check that executeApiCall was called with the right arguments expect(executeApiCall).toHaveBeenCalledTimes(1); expect(executeApiCall).toHaveBeenCalledWith( apiCallDetails, { petId: '1' } ); }); it('should handle error responses', async () => { // Set up error response const errorResponse = { error: 'Not found' }; mockApiError(404, errorResponse); // Create API call details const apiCallDetails = createTestApiCallDetails({ method: 'GET', pathTemplate: '/pets/{petId}', serverUrl: 'http://example.com/api' }); // Execute the API call const result = await executeApiCall(apiCallDetails, { petId: '999' }); // Verify the result expect(result).toBeDefined(); expect(result.statusCode).toBe(404); expect(result.success).toBe(false); expect(result.data).toEqual(errorResponse); }); }); describe('MCP Server Integration', () => { it('should create an MCP server with tools', () => { // Create an MCP server const server = new McpServer({ name: 'Test Server', version: '1.0.0' }); // Get mapped tools const mappedTools = mapOpenApiToMcpTools(openApiSpec); // Register tools with server for (const tool of mappedTools) { const { mcpToolDefinition } = tool; // Register a simple handler that just returns a test response server.tool( mcpToolDefinition.name, mcpToolDefinition.description, async () => ({ content: [{ type: 'text', text: JSON.stringify({ success: true }) }] }) ); } // Verify server has tools registered // Since we can't access server.tools directly, we'll rely on the fact that // registration succeeded without errors as a basic test expect(server).toBeDefined(); }); }); });