test: add integration test for simple mcp server (#1199)

integration-tests/simple-mcp-server.test.js

@@ -0,0 +1,70 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { test, describe, before, after } from 'node:test';
+import { strict as assert } from 'node:assert';
+import { TestRig } from './test-helper.js';
+import { spawn } from 'child_process';
+import { join } from 'path';
+import { fileURLToPath } from 'url';
+import { writeFileSync, unlinkSync } from 'fs';
+
+const __dirname = fileURLToPath(new URL('.', import.meta.url));
+const serverScriptPath = join(__dirname, './temp-server.js');
+
+const serverScript = `
+import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
+import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
+import { z } from 'zod';
+
+const server = new McpServer({
+  name: 'addition-server',
+  version: '1.0.0',
+});
+
+server.registerTool(
+  'add',
+  {
+    title: 'Addition Tool',
+    description: 'Add two numbers',
+    inputSchema: { a: z.number(), b: z.number() },
+  },
+  async ({ a, b }) => ({
+    content: [{ type: 'text', text: String(a + b) }],
+  }),
+);
+
+const transport = new StdioServerTransport();
+await server.connect(transport);
+`;
+
+describe('simple-mcp-server', () => {
+  const rig = new TestRig();
+  let child;
+
+  before(() => {
+    writeFileSync(serverScriptPath, serverScript);
+    child = spawn('node', [serverScriptPath], {
+      stdio: ['pipe', 'pipe', 'pipe'],
+    });
+    child.stderr.on('data', (data) => {
+      console.error(`stderr: ${data}`);
+    });
+    // Wait for the server to be ready
+    return new Promise((resolve) => setTimeout(resolve, 500));
+  });
+
+  after(() => {
+    child.kill();
+    unlinkSync(serverScriptPath);
+  });
+
+  test('should add two numbers', () => {
+    rig.setup('should add two numbers');
+    const output = rig.run('add 5 and 10');
+    assert.ok(output.includes('15'));
+  });
+});