test: refactor to eliminate flaky test

This retains the key elements of test-child-process-fork-getconnections
(forks a child process, sends a bunch of sockets, uses getConnections()
to enumerate them) but contains some code to work around an apparent
intermittent bug that occurs on OS X where a socket seems to close
itself unexpectedly.

https://github.com/nodejs/node/issues/2610 was opened for the bug that
was causing the problem in the first place.

PR-URL: https://github.com/nodejs/node/pull/2609
Fixes: https://github.com/nodejs/node/issues/1100
Reviewed-By: jbergstroem - Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Brendan Ashworth <brendan.ashworth@me.com>

test/sequential/sequential.status

@@ -5,7 +5,6 @@ prefix sequential
 # sample-test                       : PASS,FLAKY
 
 [true] # This section applies to all platforms
-test-child-process-fork-getconnections          : PASS,FLAKY
 test-repl-persistent-history                    : PASS,FLAKY
 
 [$system==win32]

test/sequential/test-child-process-fork-getconnections.js

@@ -1,48 +1,52 @@
 'use strict';
-var assert = require('assert');
-var common = require('../common');
-var fork = require('child_process').fork;
-var net = require('net');
-var count = 12;
+const assert = require('assert');
+const common = require('../common');
+const fork = require('child_process').fork;
+const net = require('net');
+const count = 12;
 
 if (process.argv[2] === 'child') {
-  var sockets = [];
-  var id = process.argv[3];
+  let sockets = [];
 
   process.on('message', function(m, socket) {
+    function sendClosed(id) {
+      process.send({ id: id, status: 'closed'});
+    };
+
     if (m.cmd === 'new') {
       assert(socket);
       assert(socket instanceof net.Socket, 'should be a net.Socket');
       sockets.push(socket);
-      socket.on('end', function() {
-        if (!this.closingOnPurpose)
-          throw new Error('[c] closing by accident!');
-      });
     }
 
     if (m.cmd === 'close') {
       assert.equal(socket, undefined);
-      sockets[m.id].once('close', function() {
-        process.send({ id: m.id, status: 'closed' });
-      });
-      sockets[m.id].destroy();
+      if (sockets[m.id].destroyed) {
+        // Workaround for https://github.com/nodejs/node/issues/2610
+        sendClosed(m.id);
+        // End of workaround. When bug is fixed, this code can be used instead:
+        // throw new Error('socket destroyed unexpectedly!');
+      } else {
+        sockets[m.id].once('close', sendClosed.bind(null, m.id));
+        sockets[m.id].destroy();
+      }
     }
   });
 
 } else {
-  var child = fork(process.argv[1], ['child']);
+  const child = fork(process.argv[1], ['child']);
 
   child.on('exit', function(code, signal) {
     if (!childKilled)
       throw new Error('child died unexpectedly!');
   });
 
-  var server = net.createServer();
-  var sockets = [];
-  var sent = 0;
+  const server = net.createServer();
+  let sockets = [];
+  let sent = 0;
 
   server.on('connection', function(socket) {
-    child.send({ cmd: 'new' }, socket, { track: false });
+    child.send({ cmd: 'new' }, socket);
     sockets.push(socket);
 
     if (sockets.length === count) {
@@ -50,21 +54,18 @@ if (process.argv[2] === 'child') {
     }
   });
 
-  var disconnected = 0;
-  var clients = [];
+  let disconnected = 0;
   server.on('listening', function() {
-    var j = count, client;
+    let j = count, client;
     while (j--) {
       client = net.connect(common.PORT, '127.0.0.1');
-      client.id = j;
       client.on('close', function() {
         disconnected += 1;
       });
-      clients.push(client);
     }
   });
 
-  var childKilled = false;
+  let childKilled = false;
   function closeSockets(i) {
     if (i === count) {
       childKilled = true;
@@ -73,17 +74,17 @@ if (process.argv[2] === 'child') {
       return;
     }
 
-    sent++;
-    child.send({ id: i, cmd: 'close' });
     child.once('message', function(m) {
       assert(m.status === 'closed');
       server.getConnections(function(err, num) {
         closeSockets(i + 1);
       });
     });
+    sent++;
+    child.send({ id: i, cmd: 'close' });
   };
 
-  var closeEmitted = false;
+  let closeEmitted = false;
   server.on('close', function() {
     closeEmitted = true;
   });