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, 8 deletions

diff --git a/test/parallel/test-util-format.js b/test/parallel/test-util-format.js
index c601a64d48..fd686cb6d3 100644
--- a/test/parallel/test-util-format.js
+++ b/test/parallel/test-util-format.js
@@ -249,15 +249,16 @@ assert.strictEqual(util.format('abc%', 1), 'abc% 1');
 // Errors
 const err = new Error('foo');
 assert.strictEqual(util.format(err), err.stack);
-function CustomError(msg) {
-  Error.call(this);
-  Object.defineProperty(this, 'message',
-                        { value: msg, enumerable: false });
-  Object.defineProperty(this, 'name',
-                        { value: 'CustomError', enumerable: false });
-  Error.captureStackTrace(this, CustomError);
+class CustomError extends Error {
+  constructor(msg) {
+    super();
+    Object.defineProperty(this, 'message',
+                          { value: msg, enumerable: false });
+    Object.defineProperty(this, 'name',
+                          { value: 'CustomError', enumerable: false });
+    Error.captureStackTrace(this, CustomError);
+  }
 }
-util.inherits(CustomError, Error);
 const customError = new CustomError('bar');
 assert.strictEqual(util.format(customError), customError.stack);
 // Doesn't capture stack trace