diff --git a/lib/test.js b/lib/test.js
index c6c73b9e..377a890c 100644
--- a/lib/test.js
+++ b/lib/test.js
@@ -12,7 +12,7 @@ var callBind = require('call-bind');
 var callBound = require('call-bind/callBound');
 var forEach = require('for-each');
 var inspect = require('object-inspect');
-var is = require('object-is');
+var is = require('object-is/polyfill')();
 var objectKeys = require('object-keys');
 var every = require('array.prototype.every');
 var mockProperty = require('mock-property');