run in separate thread maybe fixes it

test/fetch/long-lived-abort-controller.js

@@ -1,24 +1,39 @@
 'use strict'
 
-const http = require('node:http')
-const { fetch } = require('../../')
-const { once } = require('events')
+const { fork } = require('node:child_process')
+const { resolve: pathResolve } = require('node:path')
 const { test } = require('node:test')
-const { closeServerAsPromise } = require('../utils/node-http')
+const { fetch } = require('../../')
 const { strictEqual, fail } = require('node:assert')
 
 const isNode18 = process.version.startsWith('v18')
 
 test('long-lived-abort-controller', { skip: isNode18 }, async (t) => {
-  const server = http.createServer((req, res) => {
-    res.writeHead(200, { 'Content-Type': 'text/plain' })
-    res.write('Hello World!')
-    res.end()
-  }).listen(0)
+  // Spawn a server in a new process to avoid effects from the blocking event loop
+  const {
+    serverProcess,
+    address
+  } = await new Promise((resolve, reject) => {
+    const childProcess = fork(
+      pathResolve(__dirname, '../utils/hello-world-server.js'),
+      [],
+      { windowsHide: true }
+    )
 
-  await once(server, 'listening')
+    childProcess.on('message', (address) => {
+      resolve({
+        serverProcess: childProcess,
+        address
+      })
+    })
+    childProcess.on('error', err => {
+      reject(err)
+    })
+  })
 
-  t.after(closeServerAsPromise(server))
+  t.after(() => {
+    serverProcess.kill('SIGKILL')
+  })
 
   let emittedWarning = null
   function onWarning (value) {
@@ -36,7 +51,7 @@ test('long-lived-abort-controller', { skip: isNode18 }, async (t) => {
   // Unfortunately we are relying on GC and implementation details here.
   for (let i = 0; i < 2000; i++) {
     // make request
-    const res = await fetch(`http://localhost:${server.address().port}`, {
+    const res = await fetch(address, {
       signal: controller.signal
     })
 

test/issue-3410.js

@@ -17,7 +17,7 @@ describe('https://github.com/nodejs/undici/issues/3410', () => {
       address
     } = await new Promise((resolve, reject) => {
       const childProcess = fork(
-        pathResolve(__dirname, './utils/hello-world-server.js'),
+        pathResolve(__dirname, './utils/hello-world-server-delayed.js'),
         [],
         { windowsHide: true }
       )
@@ -56,7 +56,7 @@ describe('https://github.com/nodejs/undici/issues/3410', () => {
       address
     } = await new Promise((resolve, reject) => {
       const childProcess = fork(
-        pathResolve(__dirname, './utils/hello-world-server.js'),
+        pathResolve(__dirname, './utils/hello-world-server-delayed.js'),
         [],
         { windowsHide: true }
       )

test/utils/hello-world-server-delayed.js

@@ -0,0 +1,30 @@
+'use strict'
+
+const { createServer } = require('node:http')
+const hostname = '127.0.0.1'
+
+const server = createServer(async (req, res) => {
+  res.statusCode = 200
+  res.setHeader('Content-Type', 'text/plain')
+
+  await sendInDelayedChunks(res, 'Hello World', 125)
+  res.end()
+})
+
+async function sendInDelayedChunks (res, payload, delay) {
+  const chunks = payload.split('')
+
+  for (const chunk of chunks) {
+    await new Promise(resolve => setTimeout(resolve, delay))
+
+    res.write(chunk)
+  }
+}
+
+server.listen(0, hostname, () => {
+  if (process.send) {
+    process.send(`http://${hostname}:${server.address().port}/`)
+  } else {
+    console.log(`http://${hostname}:${server.address().port}/`)
+  }
+})

test/utils/hello-world-server.js

@@ -6,21 +6,9 @@ const hostname = '127.0.0.1'
 const server = createServer(async (req, res) => {
   res.statusCode = 200
   res.setHeader('Content-Type', 'text/plain')
-
-  await sendInDelayedChunks(res, 'Hello World', 125)
-  res.end()
+  res.end('Hello World')
 })
 
-async function sendInDelayedChunks (res, payload, delay) {
-  const chunks = payload.split('')
-
-  for (const chunk of chunks) {
-    await new Promise(resolve => setTimeout(resolve, delay))
-
-    res.write(chunk)
-  }
-}
-
 server.listen(0, hostname, () => {
   if (process.send) {
     process.send(`http://${hostname}:${server.address().port}/`)