fix: wait for stderr and stdout to complete

PR-URL: nodejs/node#43666
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Antoine du Hamel <[email protected]>

Author: MoLow

lib/internal/main/test_runner.js

@@ -8,13 +8,16 @@ const {
   ArrayPrototypeSlice,
   ArrayPrototypeSort,
   Promise,
+  PromiseAll,
+  SafeArrayIterator,
   SafeSet
 } = require('#internal/per_context/primordials')
 const {
   prepareMainThreadExecution
 } = require('#internal/bootstrap/pre_execution')
 const { spawn } = require('child_process')
 const { readdirSync, statSync } = require('fs')
+const { finished } = require('#internal/streams/end-of-stream')
 const console = require('#internal/console/global')
 const {
   codes: {
@@ -128,9 +131,10 @@ function runTestFile (path) {
         stderr += chunk
       })
 
-      child.once('exit', (code, signal) => {
+      child.once('exit', async (code, signal) => {
         if (code !== 0 || signal !== null) {
           if (!err) {
+            await PromiseAll(new SafeArrayIterator([finished(child.stderr), finished(child.stdout)]))
             err = new ERR_TEST_FAILURE('test failed', kSubtestsFailed)
             err.exitCode = code
             err.signal = signal

lib/internal/per_context/primordials.js

@@ -28,7 +28,9 @@ exports.ObjectIsExtensible = obj => Object.isExtensible(obj)
 exports.ObjectPrototypeHasOwnProperty = (obj, property) => Object.prototype.hasOwnProperty.call(obj, property)
 exports.ReflectApply = (target, self, args) => Reflect.apply(target, self, args)
 exports.Promise = Promise
+exports.PromiseAll = iterator => Promise.all(iterator)
 exports.PromiseResolve = val => Promise.resolve(val)
+exports.SafeArrayIterator = class ArrayIterator {constructor (array) { this.array = array }[Symbol.iterator] () { return this.array.values() }}
 exports.SafeMap = Map
 exports.SafeSet = Set
 exports.SafeWeakMap = WeakMap

lib/internal/streams/end-of-stream.js

@@ -0,0 +1,22 @@
+'use strict'
+
+let finished
+try {
+  ({ finished } = require('node:stream/promises'))
+} catch {
+  // node:stream/promises is not available on Node.js 14.x
+  const { finished: eos } = require('node:stream')
+  finished = function finished (stream, opts) {
+    return new Promise((resolve, reject) => {
+      eos(stream, opts, (err) => {
+        if (err) {
+          reject(err)
+        } else {
+          resolve()
+        }
+      })
+    })
+  }
+}
+
+module.exports = { finished }