diff --git a/test/common.js b/test/common.js
index ec223a1da6b950..187d26acce6056 100644
--- a/test/common.js
+++ b/test/common.js
@@ -188,19 +188,6 @@ exports.hasIPv6 = Object.keys(ifaces).some(function(name) {
   });
 });
 
-function protoCtrChain(o) {
-  var result = [];
-  for (; o; o = Object.getPrototypeOf(o)) { result.push(o.constructor); }
-  return result.join();
-}
-
-exports.indirectInstanceOf = function(obj, cls) {
-  if (obj instanceof cls) { return true; }
-  var clsChain = protoCtrChain(cls.prototype);
-  var objChain = protoCtrChain(obj);
-  return objChain.slice(-clsChain.length) === clsChain;
-};
-
 
 exports.ddCommand = function(filename, kilobytes) {
   if (exports.isWindows) {
diff --git a/test/parallel/test-assert.js b/test/parallel/test-assert.js
index d779051d7f1d35..d37b179899ca70 100644
--- a/test/parallel/test-assert.js
+++ b/test/parallel/test-assert.js
@@ -1,5 +1,5 @@
 'use strict';
-var common = require('../common');
+require('../common');
 var assert = require('assert');
 var a = require('assert');
 
@@ -10,7 +10,7 @@ function makeBlock(f) {
   };
 }
 
-assert.ok(common.indirectInstanceOf(a.AssertionError.prototype, Error),
+assert.ok(a.AssertionError.prototype instanceof Error,
           'a.AssertionError instanceof Error');
 
 assert.throws(makeBlock(a, false), a.AssertionError, 'ok(false)');
diff --git a/test/sequential/test-module-loading.js b/test/sequential/test-module-loading.js
index 2235a068ca23f0..8e7f641326e7c9 100644
--- a/test/sequential/test-module-loading.js
+++ b/test/sequential/test-module-loading.js
@@ -1,5 +1,5 @@
 'use strict';
-var common = require('../common');
+require('../common');
 var assert = require('assert');
 var path = require('path');
 var fs = require('fs');
@@ -33,25 +33,25 @@ var d4 = require('../fixtures/b/d');
 
 assert.equal(false, false, 'testing the test program.');
 
-assert.equal(true, common.indirectInstanceOf(a.A, Function));
+assert.ok(a.A instanceof Function);
 assert.equal('A', a.A());
 
-assert.equal(true, common.indirectInstanceOf(a.C, Function));
+assert.ok(a.C instanceof Function);
 assert.equal('C', a.C());
 
-assert.equal(true, common.indirectInstanceOf(a.D, Function));
+assert.ok(a.D instanceof Function);
 assert.equal('D', a.D());
 
-assert.equal(true, common.indirectInstanceOf(d.D, Function));
+assert.ok(d.D instanceof Function);
 assert.equal('D', d.D());
 
-assert.equal(true, common.indirectInstanceOf(d2.D, Function));
+assert.ok(d2.D instanceof Function);
 assert.equal('D', d2.D());
 
-assert.equal(true, common.indirectInstanceOf(d3.D, Function));
+assert.ok(d3.D instanceof Function);
 assert.equal('D', d3.D());
 
-assert.equal(true, common.indirectInstanceOf(d4.D, Function));
+assert.ok(d4.D instanceof Function);
 assert.equal('D', d4.D());
 
 assert.ok((new a.SomeClass()) instanceof c.SomeClass);
@@ -88,7 +88,7 @@ require('../fixtures/node_modules/foo');
 console.error('test name clashes');
 // this one exists and should import the local module
 var my_path = require('../fixtures/path');
-assert.ok(common.indirectInstanceOf(my_path.path_func, Function));
+assert.ok(my_path.path_func instanceof Function);
 // this one does not exist and should throw
 assert.throws(function() { require('./utils'); });
 
@@ -259,19 +259,19 @@ assert.throws(function() {
 }, 'missing path');
 
 process.on('exit', function() {
-  assert.ok(common.indirectInstanceOf(a.A, Function));
+  assert.ok(a.A instanceof Function);
   assert.equal('A done', a.A());
 
-  assert.ok(common.indirectInstanceOf(a.C, Function));
+  assert.ok(a.C instanceof Function);
   assert.equal('C done', a.C());
 
-  assert.ok(common.indirectInstanceOf(a.D, Function));
+  assert.ok(a.D instanceof Function);
   assert.equal('D done', a.D());
 
-  assert.ok(common.indirectInstanceOf(d.D, Function));
+  assert.ok(d.D instanceof Function);
   assert.equal('D done', d.D());
 
-  assert.ok(common.indirectInstanceOf(d2.D, Function));
+  assert.ok(d2.D instanceof Function);
   assert.equal('D done', d2.D());
 
   assert.equal(true, errorThrown);