test: fix flaky test-net-error-twice

On Windows there can exist some race condition where the notification of the client's `socket.destroy()` isn't received before the server writes to the socket. This race condition was more evident/reproducible on a single core system. This commit fixes the flakiness by waiting until the server's connection event handler has been called to destroy the client socket and perform the server socket write. Fixes: #4057 PR-URL: #4342 Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl> Reviewed-By: João Reis <reis@janeasystems.com>
nodejs · Fishrock123 · Aug 21, 2015 · Dec 17, 2015 · Dec 17, 2015 · Dec 14, 2015
commit 569e5eb9bba3e807a148276f43e13fce59bcb660
diff --git a/test/parallel/test-net-error-twice.js b/test/parallel/test-net-error-twice.js
@@ -1,16 +1,24 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
-var net = require('net');
+const common = require('../common');
+const assert = require('assert');
+const net = require('net');
 
-var buf = new Buffer(10 * 1024 * 1024);
+const buf = new Buffer(10 * 1024 * 1024);
 
 buf.fill(0x62);
 
-var errs = [];
+const errs = [];
+var clientSocket;
+var serverSocket;
+
+function ready() {
+  if (clientSocket && serverSocket) {
+    clientSocket.destroy();
+    serverSocket.write(buf);
+  }
+}
 
 var srv = net.createServer(function onConnection(conn) {
-  conn.write(buf);
   conn.on('error', function(err) {
     errs.push(err);
     if (errs.length > 1 && errs[0] === errs[1])
@@ -19,11 +27,14 @@ var srv = net.createServer(function onConnection(conn) {
   conn.on('close', function() {
     srv.unref();
   });
+  serverSocket = conn;
+  ready();
 }).listen(common.PORT, function() {
   var client = net.connect({ port: common.PORT });
 
   client.on('connect', function() {
-    client.destroy();
+    clientSocket = client;
+    ready();
   });
 });