test: add test for uid/gid setting in spawn

Remove a disabled test in favor of one that expects an error.

This validates (somewhat) that the underlying code is calling the
correct system call for setting UID and GID. Unlike the formerly
disabled test, it does not try to validate that the system UID/GID
setting works.

PR-URL: https://github.com/nodejs/node/pull/7084
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/disabled/test-child-process-uid-gid.js

@@ -1,60 +0,0 @@
-'use strict';
-var common = require('../common');
-var assert = require('assert');
-var spawn = require('child_process').spawn;
-var fs = require('fs');
-
-var myUid = process.getuid();
-var myGid = process.getgid();
-
-if (myUid != 0) {
-  console.error('must be run as root, otherwise the gid/uid setting will' +
-                ' fail.');
-  process.exit(1);
-}
-
-// get a different user.
-// don't care who it is, as long as it's not root
-var passwd = fs.readFileSync('/etc/passwd', 'utf8');
-passwd = passwd.trim().split(/\n/);
-
-for (var i = 0, l = passwd.length; i < l; i++) {
-  if (passwd[i].charAt(0) === '#') continue;
-  passwd[i] = passwd[i].split(':');
-  var otherName = passwd[i][0];
-  var otherUid = +passwd[i][2];
-  var otherGid = +passwd[i][3];
-  if (otherUid && otherUid !== myUid &&
-      otherGid && otherGid !== myGid &&
-      otherUid > 0) {
-    break;
-  }
-}
-if (!otherUid && !otherGid) throw new Error('failed getting passwd info.');
-
-console.error('name, id, gid = %j', [otherName, otherUid, otherGid]);
-
-var whoNumber = spawn('id', [], { uid: otherUid, gid: otherGid });
-var whoName = spawn('id', [], { uid: otherName, gid: otherGid });
-
-whoNumber.stdout.buf = 'byNumber:';
-whoName.stdout.buf = 'byName:';
-whoNumber.stdout.on('data', onData);
-whoName.stdout.on('data', onData);
-function onData(c) { this.buf += c; }
-
-whoNumber.on('exit', onExit);
-whoName.on('exit', onExit);
-
-function onExit(code) {
-  var buf = this.stdout.buf;
-  console.log(buf);
-  var expr = new RegExp('^(byName|byNumber):uid=' +
-                        otherUid +
-                        '\\(' +
-                        otherName +
-                        '\\) gid=' +
-                        otherGid +
-                        '\\(');
-  assert.ok(buf.match(expr), 'uid and gid should match ' + otherName);
-}

test/parallel/test-child-process-uid-gid.js

@@ -0,0 +1,14 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const spawn = require('child_process').spawn;
+
+const expectedError = common.isWindows ? /\bENOTSUP\b/ : /\bEPERM\b/;
+
+assert.throws(() => {
+  spawn('echo', ['fhqwhgads'], {uid: 0});
+}, expectedError);
+
+assert.throws(() => {
+  spawn('echo', ['fhqwhgads'], {gid: 0});
+}, expectedError);