Abstracted check for Node v6

tests/js/asserts.js

@@ -109,6 +109,14 @@ module.exports = {
             throw new TestFailureError(errorMessage || 'Condition expected to be true');
         }
     },
+
+    isNode: function() {
+        return typeof process == 'object' && Object.prototype.toString.call(process) == '[object process]';
+    },
+
+    isNode6: function() {
+        return this.isNode() && process.version.indexOf('v6.') == 0;
+    },
 };
 
 function TestFailureError(message) {

tests/js/list-tests.js

@@ -556,7 +556,7 @@ module.exports = BaseTest.extend({
 
             // A Node 6 regression in v8 causes an error when converting our objects to strings:
             // TypeError: Cannot convert a Symbol value to a string
-            if (typeof process != 'object' || ('' + process.version).indexOf('v6.') < 0) {
+            if (!TestCase.isNode6()) {
                 TestCase.assertEqual(list.join(' '), 'Ari Tim Bjarne');
             }