MCPRouter.test.ts•7.14 kB
/**
* 🎯 SEMANTIC INTENT: Unit tests for MCPRouter
*
* PURPOSE: Verify HTTP routing and request handling
*
* TEST STRATEGY:
* - Mock MCPProtocolHandler
* - Test routing logic (GET, POST, OPTIONS)
* - Test CORS handling
* - Test error handling
*/
import { describe, it, expect, vi, beforeEach } from 'vitest';
import { MCPRouter } from './MCPRouter';
import type { MCPProtocolHandler } from '../../application/handlers/MCPProtocolHandler';
// Mock MCPProtocolHandler
class MockMCPProtocolHandler {
handle = vi.fn();
}
describe('MCPRouter', () => {
let router: MCPRouter;
let mockHandler: MockMCPProtocolHandler;
beforeEach(() => {
mockHandler = new MockMCPProtocolHandler();
router = new MCPRouter(mockHandler as unknown as MCPProtocolHandler);
});
describe('OPTIONS requests (CORS preflight)', () => {
it('should handle OPTIONS request with CORS headers', async () => {
// Arrange
const request = new Request('http://localhost/mcp', { method: 'OPTIONS' });
// Act
const response = await router.route(request);
// Assert
expect(response.status).toBe(200); // CORSMiddleware returns 200
expect(response.headers.get('Access-Control-Allow-Origin')).toBe('*');
expect(response.headers.get('Access-Control-Allow-Methods')).toContain('POST');
});
});
describe('GET requests', () => {
it('should return info message for GET on MCP endpoint', async () => {
// Arrange
const request = new Request('http://localhost/mcp', { method: 'GET' });
// Act
const response = await router.route(request);
// Assert
expect(response.status).toBe(200);
const text = await response.text();
expect(text).toContain('MCP endpoint');
expect(text).toContain('use POST');
});
it('should return server status for GET on root', async () => {
// Arrange
const request = new Request('http://localhost/', { method: 'GET' });
// Act
const response = await router.route(request);
// Assert
expect(response.status).toBe(200);
const text = await response.text();
expect(text).toContain('Semantic Context MCP Server is running');
});
});
describe('POST requests to MCP endpoints', () => {
it('should delegate valid JSON-RPC to protocol handler', async () => {
// Arrange
const mcpRequest = {
jsonrpc: "2.0",
method: "initialize",
id: 1,
params: {}
};
const mockResponse = new Response(JSON.stringify({
jsonrpc: "2.0",
result: {},
id: 1
}));
mockHandler.handle.mockResolvedValue(mockResponse);
const request = new Request('http://localhost/mcp', {
method: 'POST',
body: JSON.stringify(mcpRequest),
headers: { 'Content-Type': 'application/json' }
});
// Act
const response = await router.route(request);
// Assert
expect(mockHandler.handle).toHaveBeenCalledWith(mcpRequest);
expect(response).toBe(mockResponse);
});
it('should handle /sse endpoint', async () => {
// Arrange
const mcpRequest = { jsonrpc: "2.0", method: "tools/list", id: 2 };
const mockResponse = new Response('{}');
mockHandler.handle.mockResolvedValue(mockResponse);
const request = new Request('http://localhost/sse', {
method: 'POST',
body: JSON.stringify(mcpRequest)
});
// Act
const response = await router.route(request);
// Assert
expect(mockHandler.handle).toHaveBeenCalledWith(mcpRequest);
});
it('should handle /mcp/* sub-paths', async () => {
// Arrange
const mcpRequest = { jsonrpc: "2.0", method: "test", id: 3 };
const mockResponse = new Response('{}');
mockHandler.handle.mockResolvedValue(mockResponse);
const request = new Request('http://localhost/mcp/v1', {
method: 'POST',
body: JSON.stringify(mcpRequest)
});
// Act
const response = await router.route(request);
// Assert
expect(mockHandler.handle).toHaveBeenCalledWith(mcpRequest);
});
});
describe('Error handling', () => {
it('should return 400 for invalid JSON', async () => {
// Arrange
const request = new Request('http://localhost/mcp', {
method: 'POST',
body: 'invalid json{',
headers: { 'Content-Type': 'application/json' }
});
// Act
const response = await router.route(request);
// Assert
expect(response.status).toBe(400);
const json = await response.json() as { error: { code: number; message: string } };
expect(json.error.code).toBe(-32700); // Parse error
expect(json.error.message).toBe('Parse error');
});
it('should log errors to console', async () => {
// Arrange
const consoleErrorSpy = vi.spyOn(console, 'error').mockImplementation(() => {});
const request = new Request('http://localhost/mcp', {
method: 'POST',
body: 'bad json'
});
// Act
await router.route(request);
// Assert
expect(consoleErrorSpy).toHaveBeenCalledWith('MCP Error:', expect.any(Error));
consoleErrorSpy.mockRestore();
});
it('should catch and return 400 for handler errors', async () => {
// Arrange
const mcpRequest = { jsonrpc: "2.0", method: "test", id: 1 };
mockHandler.handle.mockRejectedValue(new Error('Handler error'));
const request = new Request('http://localhost/mcp', {
method: 'POST',
body: JSON.stringify(mcpRequest)
});
// Act
const response = await router.route(request);
// Assert - Router catches errors in try-catch and returns 400
expect(response.status).toBe(400);
const json = await response.json() as { error?: unknown };
expect(json.error).toBeDefined();
});
});
describe('Endpoint detection', () => {
it('should recognize /mcp as MCP endpoint', async () => {
const request = new Request('http://localhost/mcp', {
method: 'POST',
body: JSON.stringify({ jsonrpc: "2.0", method: "test", id: 1 })
});
mockHandler.handle.mockResolvedValue(new Response('{}'));
await router.route(request);
expect(mockHandler.handle).toHaveBeenCalled();
});
it('should recognize /sse as MCP endpoint', async () => {
const request = new Request('http://localhost/sse', {
method: 'POST',
body: JSON.stringify({ jsonrpc: "2.0", method: "test", id: 1 })
});
mockHandler.handle.mockResolvedValue(new Response('{}'));
await router.route(request);
expect(mockHandler.handle).toHaveBeenCalled();
});
it('should not treat /other as MCP endpoint', async () => {
const request = new Request('http://localhost/other', { method: 'GET' });
const response = await router.route(request);
const text = await response.text();
expect(text).toContain('Semantic Context MCP Server is running');
expect(mockHandler.handle).not.toHaveBeenCalled();
});
});
});