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, 16 insertions, 17 deletions

diff --git a/test/sequential/test-stream2-fs.js b/test/sequential/test-stream2-fs.js
index e2da2dca64..3d06abc921 100644
--- a/test/sequential/test-stream2-fs.js
+++ b/test/sequential/test-stream2-fs.js
@@ -34,27 +34,26 @@ const size = fs.statSync(file).size;
 
 const expectLengths = [1024];
 
-const util = require('util');
 const Stream = require('stream');
 
-util.inherits(TestWriter, Stream);
+class TestWriter extends Stream {
+  constructor() {
+    super();
+    this.buffer = [];
+    this.length = 0;
+  }
 
-function TestWriter() {
-  Stream.apply(this);
-  this.buffer = [];
-  this.length = 0;
-}
-
-TestWriter.prototype.write = function(c) {
-  this.buffer.push(c.toString());
-  this.length += c.length;
-  return true;
-};
+  write(c) {
+    this.buffer.push(c.toString());
+    this.length += c.length;
+    return true;
+  }
 
-TestWriter.prototype.end = function(c) {
-  if (c) this.buffer.push(c.toString());
-  this.emit('results', this.buffer);
-};
+  end(c) {
+    if (c) this.buffer.push(c.toString());
+    this.emit('results', this.buffer);
+  }
+}
 
 const r = new FSReadable(file);
 const w = new TestWriter();