test: refactor test-fs-stat

* add `use strict'
* change checks that `this` is mapped to `global` in sloppy mode to
  checks that `this` is `undefined`
* modify arguments to assertions to match docs (actual first, expected
  second)
* add blank line below `common` declaration per test writing guide
* use `assert.ifError()` as appropriate

PR-URL: https://github.com/nodejs/node/pull/14645
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

test/parallel/test-fs-stat.js

@@ -19,15 +19,19 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-/* eslint-disable strict */
+'use strict';
 const common = require('../common');
+
 const assert = require('assert');
 const fs = require('fs');
 
 fs.stat('.', common.mustCall(function(err, stats) {
   assert.ifError(err);
   assert.ok(stats.mtime instanceof Date);
-  assert.strictEqual(this, global);
+  // Confirm that we are not running in the context of the internal binding
+  // layer.
+  // Ref: https://github.com/nodejs/node/commit/463d6bac8b349acc462d345a6e298a76f7d06fb1
+  assert.strictEqual(this, undefined);
 }));
 
 fs.stat('.', common.mustCall(function(err, stats) {
@@ -38,22 +42,31 @@ fs.stat('.', common.mustCall(function(err, stats) {
 fs.lstat('.', common.mustCall(function(err, stats) {
   assert.ifError(err);
   assert.ok(stats.mtime instanceof Date);
-  assert.strictEqual(this, global);
+  // Confirm that we are not running in the context of the internal binding
+  // layer.
+  // Ref: https://github.com/nodejs/node/commit/463d6bac8b349acc462d345a6e298a76f7d06fb1
+  assert.strictEqual(this, undefined);
 }));
 
 // fstat
 fs.open('.', 'r', undefined, common.mustCall(function(err, fd) {
-  assert.ok(!err);
+  assert.ifError(err);
   assert.ok(fd);
 
   fs.fstat(fd, common.mustCall(function(err, stats) {
     assert.ifError(err);
     assert.ok(stats.mtime instanceof Date);
     fs.close(fd, assert.ifError);
-    assert.strictEqual(this, global);
+    // Confirm that we are not running in the context of the internal binding
+    // layer.
+    // Ref: https://github.com/nodejs/node/commit/463d6bac8b349acc462d345a6e298a76f7d06fb1
+    assert.strictEqual(this, undefined);
   }));
 
-  assert.strictEqual(this, global);
+  // Confirm that we are not running in the context of the internal binding
+  // layer.
+  // Ref: https://github.com/nodejs/node/commit/463d6bac8b349acc462d345a6e298a76f7d06fb1
+  assert.strictEqual(this, null);
 }));
 
 // fstatSync
@@ -72,13 +85,13 @@ fs.open('.', 'r', undefined, common.mustCall(function(err, fd) {
 
 fs.stat(__filename, common.mustCall(function(err, s) {
   assert.ifError(err);
-  assert.strictEqual(false, s.isDirectory());
+  assert.strictEqual(s.isDirectory(), false);
-  assert.strictEqual(true, s.isFile());
+  assert.strictEqual(s.isFile(), true);
-  assert.strictEqual(false, s.isSocket());
+  assert.strictEqual(s.isSocket(), false);
-  assert.strictEqual(false, s.isBlockDevice());
+  assert.strictEqual(s.isBlockDevice(), false);
-  assert.strictEqual(false, s.isCharacterDevice());
+  assert.strictEqual(s.isCharacterDevice(), false);
-  assert.strictEqual(false, s.isFIFO());
+  assert.strictEqual(s.isFIFO(), false);
-  assert.strictEqual(false, s.isSymbolicLink());
+  assert.strictEqual(s.isSymbolicLink(), false);
   const keys = [
     'dev', 'mode', 'nlink', 'uid',
     'gid', 'rdev', 'ino', 'size',