TeamCity MCP Server

/** * Integration test for MCP stdio transport compliance * * Verifies that the server strictly adheres to the MCP stdio specification: * - ONLY valid JSON-RPC messages go to stdout * - All logging goes to stderr * - No dotenv or other library output pollutes stdout * * This test prevents regressions of issues like: * - Winston Console transport writing to stdout * - Dotenv debug messages appearing on stdout * - Any other stdout pollution that breaks MCP clients */ import { spawn } from 'child_process'; import { join } from 'path'; import packageJson from '../../package.json'; describe('MCP stdio transport compliance', () => { const serverPath = join(__dirname, '../../dist/index.js'); const timeout = 10000; it( 'should only output valid JSON-RPC to stdout during handshake', async () => { const server = spawn('node', [serverPath], { stdio: ['pipe', 'pipe', 'pipe'], env: { ...process.env, TEAMCITY_URL: process.env['TEAMCITY_URL'] ?? 'http://localhost:8111', TEAMCITY_TOKEN: process.env['TEAMCITY_TOKEN'] ?? 'test-token', DOTENV_CONFIG_QUIET: 'true', }, }); let stdoutData = ''; let stderrData = ''; let initResponse: { result?: { serverInfo?: { name: string; version: string }; protocolVersion?: string }; } | null = null; const stdoutPromise = new Promise<void>((resolve, reject) => { server.stdout.on('data', (data) => { stdoutData += data.toString(); // Try to parse each line as JSON-RPC const lines = stdoutData.split('\n'); for (const line of lines) { if (!line.trim()) continue; try { const parsed = JSON.parse(line); // Verify it's a valid JSON-RPC message expect(parsed).toHaveProperty('jsonrpc'); expect(parsed.jsonrpc).toBe('2.0'); // Should have either id (response) or method (notification/request) expect(parsed.id !== undefined || parsed.method !== undefined).toBe(true); if (parsed.result?.serverInfo !== undefined) { initResponse = parsed; resolve(); } } catch (e) { reject(new Error(`Invalid JSON on stdout: ${line}\nError: ${String(e)}`)); } } }); }); server.stderr.on('data', (data) => { stderrData += data.toString(); }); // Send initialize request const initRequest = { jsonrpc: '2.0', id: 1, method: 'initialize', params: { protocolVersion: '2024-11-05', capabilities: {}, clientInfo: { name: 'test-client', version: '1.0.0', }, }, }; server.stdin.write(`${JSON.stringify(initRequest)}\n`); await Promise.race([ stdoutPromise, new Promise((_, reject) => setTimeout(() => reject(new Error('Timeout waiting for initialize response')), timeout) ), ]); // Verify we got a valid initialize response expect(initResponse).not.toBeNull(); const response = initResponse!; expect(response.result).toHaveProperty('serverInfo'); expect(response.result?.serverInfo?.name).toBe('teamcity-mcp'); expect(response.result?.serverInfo?.version).toMatch(/^\d+\.\d+\.\d+/); expect(response.result?.protocolVersion).toBe('2024-11-05'); // Verify stderr contains logging (not stdout) expect(stderrData).toContain('TeamCity MCP Server'); // Verify NO dotenv messages on stdout expect(stdoutData).not.toContain('dotenv'); expect(stdoutData).not.toContain('[dotenv'); // Clean up server.kill(); await new Promise((resolve) => server.on('close', resolve)); }, timeout ); it( 'should route all winston logging to stderr, not stdout', async () => { const server = spawn('node', [serverPath], { stdio: ['pipe', 'pipe', 'pipe'], env: { ...process.env, TEAMCITY_URL: process.env['TEAMCITY_URL'] ?? 'http://localhost:8111', TEAMCITY_TOKEN: process.env['TEAMCITY_TOKEN'] ?? 'test-token', DOTENV_CONFIG_QUIET: 'true', }, }); let stdoutBuffer = ''; let stderrData = ''; let validJsonRpcCount = 0; server.stdout.on('data', (data) => { stdoutBuffer += data.toString(); }); server.stderr.on('data', (data) => { stderrData += data.toString(); }); // Send initialize + initialized server.stdin.write( `${JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'initialize', params: { protocolVersion: '2024-11-05', capabilities: {}, clientInfo: { name: 'test', version: '1.0.0' }, }, })}\n` ); await new Promise((resolve) => setTimeout(resolve, 1000)); server.stdin.write( `${JSON.stringify({ jsonrpc: '2.0', method: 'notifications/initialized', })}\n` ); // Request tools list (triggers info logging) server.stdin.write( `${JSON.stringify({ jsonrpc: '2.0', id: 2, method: 'tools/list', })}\n` ); await new Promise((resolve) => setTimeout(resolve, 2000)); // Verify all stdout lines are valid JSON-RPC const lines = stdoutBuffer.split('\n'); for (const line of lines) { if (!line.trim()) continue; const parsed = JSON.parse(line); expect(parsed).toHaveProperty('jsonrpc'); expect(parsed.jsonrpc).toBe('2.0'); validJsonRpcCount++; } // Should have received at least 2 responses (initialize + tools/list) expect(validJsonRpcCount).toBeGreaterThanOrEqual(2); // Verify logging went to stderr expect(stderrData).toContain('TeamCity MCP Server'); // Verify NO winston log format indicators on stdout expect(stdoutBuffer).not.toMatch(/\[teamcity-mcp\]/); expect(stdoutBuffer).not.toMatch(/\d{2}:\d{2}:\d{2}/); // timestamp format expect(stdoutBuffer).not.toContain('[32minfo[39m'); // colored info expect(stdoutBuffer).not.toContain('[33mwarn[39m'); // colored warn server.kill(); await new Promise((resolve) => server.on('close', resolve)); }, timeout ); it( 'should report correct server version from package.json', async () => { const server = spawn('node', [serverPath], { stdio: ['pipe', 'pipe', 'pipe'], env: { ...process.env, TEAMCITY_URL: 'http://localhost:8111', TEAMCITY_TOKEN: 'test-token', DOTENV_CONFIG_QUIET: 'true', }, }); let version: string | null = null; const versionPromise = new Promise<void>((resolve) => { server.stdout.on('data', (data) => { const lines = data.toString().split('\n'); for (const line of lines) { if (line.trim() === '') continue; try { const parsed = JSON.parse(line); if (parsed.result?.serverInfo?.version !== undefined) { version = parsed.result.serverInfo.version; resolve(); } } catch { // Ignore parse errors } } }); }); server.stdin.write( `${JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'initialize', params: { protocolVersion: '2024-11-05', capabilities: {}, clientInfo: { name: 'test', version: '1.0.0' }, }, })}\n` ); await Promise.race([ versionPromise, new Promise((_, reject) => setTimeout(() => reject(new Error('Timeout')), timeout)), ]); // Read the actual version from package.json expect(version).toBe(packageJson.version); expect(version).not.toBe('0.1.0'); // Ensure not hardcoded server.kill(); await new Promise((resolve) => server.on('close', resolve)); }, timeout ); });