diff --git a/test/parallel/test-child-process-default-options.js b/test/parallel/test-child-process-default-options.js
index d913ea6c4a55e9..f11a2678f66f5a 100644
--- a/test/parallel/test-child-process-default-options.js
+++ b/test/parallel/test-child-process-default-options.js
@@ -4,11 +4,9 @@ var assert = require('assert');
 
 var spawn = require('child_process').spawn;
 
-var isWindows = common.isWindows;
-
 process.env.HELLO = 'WORLD';
 
-if (isWindows) {
+if (common.isWindows) {
   var child = spawn('cmd.exe', ['/c', 'set'], {});
 } else {
   var child = spawn('/usr/bin/env', [], {});
diff --git a/test/parallel/test-child-process-env.js b/test/parallel/test-child-process-env.js
index 0e53180309958f..1374c2332c2cc7 100644
--- a/test/parallel/test-child-process-env.js
+++ b/test/parallel/test-child-process-env.js
@@ -4,8 +4,6 @@ var assert = require('assert');
 
 var spawn = require('child_process').spawn;
 
-var isWindows = common.isWindows;
-
 var env = {
   'HELLO': 'WORLD'
 };
@@ -13,7 +11,7 @@ env.__proto__ = {
   'FOO': 'BAR'
 };
 
-if (isWindows) {
+if (common.isWindows) {
   var child = spawn('cmd.exe', ['/c', 'set'], {env: env});
 } else {
   var child = spawn('/usr/bin/env', [], {env: env});
diff --git a/test/parallel/test-child-process-kill.js b/test/parallel/test-child-process-kill.js
index 0d781b2eefc249..745816bb68766d 100644
--- a/test/parallel/test-child-process-kill.js
+++ b/test/parallel/test-child-process-kill.js
@@ -4,14 +4,12 @@ var assert = require('assert');
 
 var spawn = require('child_process').spawn;
 
-var is_windows = common.isWindows;
-
 var exitCode;
 var termSignal;
 var gotStdoutEOF = false;
 var gotStderrEOF = false;
 
-var cat = spawn(is_windows ? 'cmd' : 'cat');
+var cat = spawn(common.isWindows ? 'cmd' : 'cat');
 
 
 cat.stdout.on('end', function() {
diff --git a/test/parallel/test-child-process-stdin.js b/test/parallel/test-child-process-stdin.js
index 5591f00827ef0d..c12b24579375dc 100644
--- a/test/parallel/test-child-process-stdin.js
+++ b/test/parallel/test-child-process-stdin.js
@@ -3,9 +3,8 @@ var common = require('../common');
 var assert = require('assert');
 
 var spawn = require('child_process').spawn;
-var is_windows = common.isWindows;
 
-var cat = spawn(is_windows ? 'more' : 'cat');
+var cat = spawn(common.isWindows ? 'more' : 'cat');
 cat.stdin.write('hello');
 cat.stdin.write(' ');
 cat.stdin.write('world');
@@ -51,7 +50,7 @@ cat.on('exit', function(status) {
 
 cat.on('close', function() {
   closed = true;
-  if (is_windows) {
+  if (common.isWindows) {
     assert.equal('hello world\r\n', response);
   } else {
     assert.equal('hello world', response);
@@ -61,7 +60,7 @@ cat.on('close', function() {
 process.on('exit', function() {
   assert.equal(0, exitStatus);
   assert(closed);
-  if (is_windows) {
+  if (common.isWindows) {
     assert.equal('hello world\r\n', response);
   } else {
     assert.equal('hello world', response);
diff --git a/test/parallel/test-fs-chmod.js b/test/parallel/test-fs-chmod.js
index 399943112352d2..11c8bb6168916e 100644
--- a/test/parallel/test-fs-chmod.js
+++ b/test/parallel/test-fs-chmod.js
@@ -7,7 +7,6 @@ var got_error = false;
 var success_count = 0;
 var mode_async;
 var mode_sync;
-var is_windows = common.isWindows;
 
 // Need to hijack fs.open/close to make sure that things
 // get closed once they're opened.
@@ -44,7 +43,7 @@ function closeSync() {
 
 
 // On Windows chmod is only able to manipulate read-only bit
-if (is_windows) {
+if (common.isWindows) {
   mode_async = 0o400;   // read-only
   mode_sync = 0o600;    // read-write
 } else {
@@ -61,14 +60,14 @@ fs.chmod(file1, mode_async.toString(8), function(err) {
   } else {
     console.log(fs.statSync(file1).mode);
 
-    if (is_windows) {
+    if (common.isWindows) {
       assert.ok((fs.statSync(file1).mode & 0o777) & mode_async);
     } else {
       assert.equal(mode_async, fs.statSync(file1).mode & 0o777);
     }
 
     fs.chmodSync(file1, mode_sync);
-    if (is_windows) {
+    if (common.isWindows) {
       assert.ok((fs.statSync(file1).mode & 0o777) & mode_sync);
     } else {
       assert.equal(mode_sync, fs.statSync(file1).mode & 0o777);
@@ -89,14 +88,14 @@ fs.open(file2, 'a', function(err, fd) {
     } else {
       console.log(fs.fstatSync(fd).mode);
 
-      if (is_windows) {
+      if (common.isWindows) {
         assert.ok((fs.fstatSync(fd).mode & 0o777) & mode_async);
       } else {
         assert.equal(mode_async, fs.fstatSync(fd).mode & 0o777);
       }
 
       fs.fchmodSync(fd, mode_sync);
-      if (is_windows) {
+      if (common.isWindows) {
         assert.ok((fs.fstatSync(fd).mode & 0o777) & mode_sync);
       } else {
         assert.equal(mode_sync, fs.fstatSync(fd).mode & 0o777);
diff --git a/test/parallel/test-fs-realpath.js b/test/parallel/test-fs-realpath.js
index 22cd538915902a..9082e1d65f4d0e 100644
--- a/test/parallel/test-fs-realpath.js
+++ b/test/parallel/test-fs-realpath.js
@@ -5,13 +5,12 @@ var fs = require('fs');
 var path = require('path');
 var exec = require('child_process').exec;
 var async_completed = 0, async_expected = 0, unlink = [];
-var isWindows = common.isWindows;
 var skipSymlinks = false;
 
 common.refreshTmpDir();
 
 var root = '/';
-if (isWindows) {
+if (common.isWindows) {
   // something like "C:\\"
   root = process.cwd().substr(0, 3);
 
@@ -292,7 +291,7 @@ function test_relative_input_cwd(callback) {
 
 function test_deep_symlink_mix(callback) {
   console.log('test_deep_symlink_mix');
-  if (isWindows) {
+  if (common.isWindows) {
     // This one is a mix of files and directories, and it's quite tricky
     // to get the file/dir links sorted out correctly.
     console.log('1..0 # Skipped: symlink test (no privs)');
@@ -503,7 +502,7 @@ function test_lying_cache_liar(cb) {
                 '/a/b' : '/a/b',
                 '/a/b/c' : '/a/b',
                 '/a/b/d' : '/a/b/d' };
-  if (isWindows) {
+  if (common.isWindows) {
     var wc = {};
     Object.keys(cache).forEach(function(k) {
       wc[ path.resolve(k) ] = path.resolve(cache[k]);
diff --git a/test/parallel/test-fs-symlink.js b/test/parallel/test-fs-symlink.js
index 78eca54c4dc213..199add4a1ba724 100644
--- a/test/parallel/test-fs-symlink.js
+++ b/test/parallel/test-fs-symlink.js
@@ -9,8 +9,6 @@ var expected_async = 4;
 var linkTime;
 var fileTime;
 
-var is_windows = common.isWindows;
-
 common.refreshTmpDir();
 
 var runtest = function(skip_symlinks) {
@@ -57,7 +55,7 @@ var runtest = function(skip_symlinks) {
   });
 };
 
-if (is_windows) {
+if (common.isWindows) {
   // On Windows, creating symlinks requires admin privileges.
   // We'll only try to run symlink test if we have enough privileges.
   exec('whoami /priv', function(err, o) {
diff --git a/test/parallel/test-fs-utimes.js b/test/parallel/test-fs-utimes.js
index 71abc3ef9baa35..292636b1b69108 100644
--- a/test/parallel/test-fs-utimes.js
+++ b/test/parallel/test-fs-utimes.js
@@ -4,8 +4,6 @@ var assert = require('assert');
 var util = require('util');
 var fs = require('fs');
 
-var is_windows = common.isWindows;
-
 var tests_ok = 0;
 var tests_run = 0;
 
@@ -99,7 +97,7 @@ function runTest(atime, mtime, callback) {
       expect_errno('utimes', 'foobarbaz', err, 'ENOENT');
 
       // don't close this fd
-      if (is_windows) {
+      if (common.isWindows) {
         fd = fs.openSync(__filename, 'r+');
       } else {
         fd = fs.openSync(__filename, 'r');
diff --git a/test/parallel/test-fs-write-file-sync.js b/test/parallel/test-fs-write-file-sync.js
index 841bad4839d497..37373404daf20e 100644
--- a/test/parallel/test-fs-write-file-sync.js
+++ b/test/parallel/test-fs-write-file-sync.js
@@ -3,7 +3,6 @@ var common = require('../common');
 var assert = require('assert');
 var path = require('path');
 var fs = require('fs');
-var isWindows = common.isWindows;
 var openCount = 0;
 var mode;
 var content;
@@ -20,7 +19,7 @@ var mask = process.umask(0o000);
 
 // On Windows chmod is only able to manipulate read-only bit. Test if creating
 // the file in read-only mode works.
-if (isWindows) {
+if (common.isWindows) {
   mode = 0o444;
 } else {
   mode = 0o755;
diff --git a/test/parallel/test-module-globalpaths-nodepath.js b/test/parallel/test-module-globalpaths-nodepath.js
index 5beb633bb793d8..3369df0676015b 100644
--- a/test/parallel/test-module-globalpaths-nodepath.js
+++ b/test/parallel/test-module-globalpaths-nodepath.js
@@ -4,12 +4,10 @@ var assert = require('assert');
 
 var module = require('module');
 
-var isWindows = common.isWindows;
-
 var partA, partB;
 var partC = '';
 
-if (isWindows) {
+if (common.isWindows) {
   partA = 'C:\\Users\\Rocko Artischocko\\AppData\\Roaming\\npm';
   partB = 'C:\\Program Files (x86)\\nodejs\\';
   process.env['NODE_PATH'] = partA + ';' + partB + ';' + partC;
diff --git a/test/parallel/test-module-nodemodulepaths.js b/test/parallel/test-module-nodemodulepaths.js
index 1a520ac5822f3b..0c70de9f285c3c 100644
--- a/test/parallel/test-module-nodemodulepaths.js
+++ b/test/parallel/test-module-nodemodulepaths.js
@@ -4,11 +4,9 @@ var assert = require('assert');
 
 var module = require('module');
 
-var isWindows = common.isWindows;
-
 var file, delimiter, paths;
 
-if (isWindows) {
+if (common.isWindows) {
   file = 'C:\\Users\\Rocko Artischocko\\node_stuff\\foo';
   delimiter = '\\';
 } else {
diff --git a/test/parallel/test-path.js b/test/parallel/test-path.js
index 10776b93c85948..c13b8d4efd1540 100644
--- a/test/parallel/test-path.js
+++ b/test/parallel/test-path.js
@@ -4,8 +4,6 @@ var assert = require('assert');
 
 var path = require('path');
 
-var isWindows = common.isWindows;
-
 var f = __filename;
 
 assert.equal(path.basename(f), 'test-path.js');
@@ -33,7 +31,7 @@ assert.equal(path.posix.basename('basename.ext\\\\'), 'basename.ext\\\\');
 
 // POSIX filenames may include control characters
 // c.f. http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html
-if (!isWindows) {
+if (!common.isWindows) {
   var controlCharFilename = 'Icon' + String.fromCharCode(13);
   assert.equal(path.basename('/a/b/' + controlCharFilename),
                controlCharFilename);
@@ -42,7 +40,7 @@ if (!isWindows) {
 assert.equal(path.extname(f), '.js');
 
 assert.equal(path.dirname(f).substr(-13),
-             isWindows ? 'test\\parallel' : 'test/parallel');
+             common.isWindows ? 'test\\parallel' : 'test/parallel');
 assert.equal(path.dirname('/a/b/'), '/a');
 assert.equal(path.dirname('/a/b'), '/a');
 assert.equal(path.dirname('/a'), '/');
@@ -194,7 +192,7 @@ var joinTests =
     ];
 
 // Windows-specific join tests
-if (isWindows) {
+if (common.isWindows) {
   joinTests = joinTests.concat(
     [// UNC path expected
      [['//foo/bar'], '//foo/bar/'],
@@ -246,7 +244,7 @@ if (isWindows) {
 // Run the join tests.
 joinTests.forEach(function(test) {
   var actual = path.join.apply(path, test[0]);
-  var expected = isWindows ? test[1].replace(/\//g, '\\') : test[1];
+  var expected = common.isWindows ? test[1].replace(/\//g, '\\') : test[1];
   var message = 'path.join(' + test[0].map(JSON.stringify).join(',') + ')' +
                 '\n  expect=' + JSON.stringify(expected) +
                 '\n  actual=' + JSON.stringify(actual);
@@ -306,7 +304,7 @@ assert.equal(path.posix.normalize('a//b//./c'), 'a/b/c');
 assert.equal(path.posix.normalize('a//b//.'), 'a/b');
 
 // path.resolve tests
-if (isWindows) {
+if (common.isWindows) {
   // windows
   var resolveTests =
       // arguments                                    result
@@ -360,7 +358,7 @@ assert.equal(path.posix.isAbsolute('bar/'), false);
 assert.equal(path.posix.isAbsolute('./baz'), false);
 
 // path.relative tests
-if (isWindows) {
+if (common.isWindows) {
   // windows
   var relativeTests =
       // arguments                     result
@@ -409,7 +407,7 @@ assert.equal(path.win32.delimiter, ';');
 assert.equal(path.posix.delimiter, ':');
 
 
-if (isWindows)
+if (common.isWindows)
   assert.deepEqual(path, path.win32, 'should be win32 path module');
 else
   assert.deepEqual(path, path.posix, 'should be posix path module');
diff --git a/test/pummel/test-child-process-spawn-loop.js b/test/pummel/test-child-process-spawn-loop.js
index 3254bec134fb9d..7e686cada244b3 100644
--- a/test/pummel/test-child-process-spawn-loop.js
+++ b/test/pummel/test-child-process-spawn-loop.js
@@ -4,8 +4,6 @@ var assert = require('assert');
 
 var spawn = require('child_process').spawn;
 
-var is_windows = common.isWindows;
-
 var SIZE = 1000 * 1024;
 var N = 40;
 var finished = false;
@@ -25,7 +23,7 @@ function doSpawn(i) {
 
   child.on('close', function() {
     // + 1 for \n or + 2 for \r\n on Windows
-    assert.equal(SIZE + (is_windows ? 2 : 1), count);
+    assert.equal(SIZE + (common.isWindows ? 2 : 1), count);
     if (i < N) {
       doSpawn(i + 1);
     } else {