test: use ES6 classes instead of util.inherits

PR-URL: https://github.com/nodejs/node/pull/16938
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/test/parallel/test-stream-writable-null.js b/test/parallel/test-stream-writable-null.js
index d8e90e5c4e..f1b91dee21 100644
--- a/test/parallel/test-stream-writable-null.js
+++ b/test/parallel/test-stream-writable-null.js
@@ -3,18 +3,17 @@ const common = require('../common');
 const assert = require('assert');
 
 const stream = require('stream');
-const util = require('util');
 
-function MyWritable(options) {
-  stream.Writable.call(this, options);
-}
-
-util.inherits(MyWritable, stream.Writable);
+class MyWritable extends stream.Writable {
+  constructor(opt) {
+    super(opt);
+  }
 
-MyWritable.prototype._write = function(chunk, encoding, callback) {
-  assert.notStrictEqual(chunk, null);
-  callback();
-};
+  _write(chunk, encoding, callback) {
+    assert.notStrictEqual(chunk, null);
+    callback();
+  }
+}
 
 common.expectsError(
   () => {