test: Refactored mcp tests to listen on new port for every streaming test, removed unncessary shutdown of process (#3420)

Author: bizob2828

test/versioned/mcp-sdk/client-stdio.test.js

@@ -25,9 +25,6 @@ test.beforeEach(async (ctx) => {
 
   const { Client } = require('@modelcontextprotocol/sdk/client/index.js')
   const { StdioClientTransport } = require('@modelcontextprotocol/sdk/client/stdio.js')
-  const pkgVersion = helper.readPackageVersion(__dirname, '@modelcontextprotocol/sdk')
-  ctx.nr.pkgVersion = pkgVersion
-
   ctx.nr.transport = new StdioClientTransport({
     command: 'node',
     args: ['stdio-server.js']
@@ -42,13 +39,15 @@ test.beforeEach(async (ctx) => {
 })
 
 test.afterEach(async (ctx) => {
-  ctx.nr.client.close()
+  await ctx.nr.client.close()
+  await ctx.nr.transport.close()
   helper.unloadAgent(ctx.nr.agent)
   removeModules(['@modelcontextprotocol/sdk/client/index.js', '@modelcontextprotocol/sdk/client/stdio.js'])
 })
 
 test('should log tracking metrics', function(t) {
-  const { agent, pkgVersion } = t.nr
+  const { agent } = t.nr
+  const pkgVersion = helper.readPackageVersion(__dirname, '@modelcontextprotocol/sdk')
   assertPackageMetrics({ agent, pkg: '@modelcontextprotocol/sdk', version: pkgVersion })
 })
 

test/versioned/mcp-sdk/client-streaming.test.js

@@ -11,9 +11,6 @@ const assert = require('node:assert')
 const { removeModules } = require('../../lib/cache-buster')
 const helper = require('../../lib/agent_helper')
 const { assertPackageMetrics, assertSegments, assertSpanKind } = require('../../lib/custom-assertions')
-const { readFile } = require('node:fs/promises')
-const path = require('node:path')
-
 const {
   MCP
 } = require('../../../lib/metrics/names')
@@ -28,18 +25,14 @@ test.beforeEach(async (ctx) => {
 
   const { Client } = require('@modelcontextprotocol/sdk/client/index.js')
   const { StreamableHTTPClientTransport } = require('@modelcontextprotocol/sdk/client/streamableHttp.js')
-  const pkg = await readFile(path.join(__dirname, '/node_modules/@modelcontextprotocol/sdk/package.json'))
-  const { version: pkgVersion } = JSON.parse(pkg.toString())
-  ctx.nr.pkgVersion = pkgVersion
-
   // Set up server
   const McpTestServer = require('./streaming-server')
   ctx.nr.mcpServer = new McpTestServer()
-  await ctx.nr.mcpServer.start()
+  const port = await ctx.nr.mcpServer.start()
 
   // Set up client
   ctx.nr.transport = new StreamableHTTPClientTransport(
-    new URL('http://localhost:3000/mcp')
+    new URL(`http://localhost:${port}/mcp`)
   )
   ctx.nr.client = new Client(
     {
@@ -51,18 +44,24 @@ test.beforeEach(async (ctx) => {
 })
 
 test.afterEach(async (ctx) => {
+  await ctx.nr.client.close()
+  await ctx.nr.transport.close()
   await ctx.nr.mcpServer.stop()
-  ctx.nr.client.close()
   helper.unloadAgent(ctx.nr.agent)
   removeModules([
     '@modelcontextprotocol/sdk/client/index.js',
-    '@modelcontextprotocol/sdk/client/streamableHttp.js',
-    './streaming-server.js'
+    '@modelcontextprotocol/sdk/client/streamableHttp.js'
   ])
 })
 
+test('should log package tracking metrics', (t) => {
+  const { agent } = t.nr
+  const version = helper.readPackageVersion(__dirname, '@modelcontextprotocol/sdk')
+  assertPackageMetrics({ agent, pkg: '@modelcontextprotocol/sdk', version })
+})
+
 test('should create span for callTool', (t, end) => {
-  const { agent, client, pkgVersion } = t.nr
+  const { agent, client } = t.nr
   helper.runInTransaction(agent, async (tx) => {
     const result = await client.callTool({
       name: 'echo',
@@ -80,14 +79,13 @@ test('should create span for callTool', (t, end) => {
         { name, kind: 'internal' }
       ]
     })
-    assertPackageMetrics({ agent, pkg: '@modelcontextprotocol/sdk', version: pkgVersion })
 
     end()
   })
 })
 
 test('should create span for readResource', (t, end) => {
-  const { agent, client, pkgVersion } = t.nr
+  const { agent, client } = t.nr
   helper.runInTransaction(agent, async (tx) => {
     const resource = await client.readResource({
       uri: 'echo://hello-world',
@@ -106,14 +104,12 @@ test('should create span for readResource', (t, end) => {
       ]
     })
 
-    assertPackageMetrics({ agent, pkg: '@modelcontextprotocol/sdk', version: pkgVersion })
-
     end()
   })
 })
 
 test('should create span for getPrompt', (t, end) => {
-  const { agent, client, pkgVersion } = t.nr
+  const { agent, client } = t.nr
   helper.runInTransaction(agent, async (tx) => {
     const prompt = await client.getPrompt({
       name: 'echo',
@@ -135,8 +131,6 @@ test('should create span for getPrompt', (t, end) => {
       ]
     })
 
-    assertPackageMetrics({ agent, pkg: '@modelcontextprotocol/sdk', version: pkgVersion })
-
     end()
   })
 })

test/versioned/mcp-sdk/stdio-server.js

@@ -19,11 +19,6 @@ async function main() {
     },
   })
 
-  // Set up auto-shutdown after first request
-  const shutdown = () => {
-    process.exit(0)
-  }
-
   server.registerResource(
     'echo',
     new ResourceTemplate('echo://{message}', { list: undefined }),
@@ -38,7 +33,6 @@ async function main() {
           text: `Resource echo: ${message}`
         }]
       }
-      setTimeout(shutdown, 100)
       return result
     }
   )
@@ -52,7 +46,6 @@ async function main() {
     },
     async ({ message }) => {
       const result = { content: [{ type: 'text', text: `Tool echo: ${message}` }] }
-      setTimeout(shutdown, 100)
       return result
     }
   )
@@ -74,7 +67,6 @@ async function main() {
           }
         }]
       }
-      setTimeout(shutdown, 100)
       return result
     }
   )

test/versioned/mcp-sdk/streaming-server.js

@@ -24,7 +24,6 @@ class McpTestServer {
     this.transport = new StreamableHTTPServerTransport({
       sessionIdGenerator: undefined,
       enableDnsRebindingProtection: true,
-      allowedHosts: ['127.0.0.1:3000', 'localhost:3000']
     })
 
     this.app = express()
@@ -110,19 +109,21 @@ class McpTestServer {
   }
 
   async start() {
+    const self = this
     await this.server.connect(this.transport)
-    const PORT = process.env.PORT || 3000
     return new Promise((resolve) => {
-      this.expressServer = this.app.listen(PORT, () => {
-        resolve()
+      this.expressServer = this.app.listen(0, function onListen() {
+        const port = this.address().port
+        self.transport._allowedHosts = [`127.0.0.1:${port}`, `localhost:${port}`]
+        resolve(port)
       })
     })
   }
 
   async stop() {
-    if (this.transport) {
-      await this.transport.close()
-    }
+    await this.transport.close()
+    this.server.close()
+
     return new Promise((resolve, reject) => {
       if (this.expressServer) {
         this.expressServer.close((err) => {