The Tor Browser / file revision

 /// Copyright (c) 2012 Ecma International.  All rights reserved. 

 /// Ecma International makes this code available under the terms and conditions set

 /// forth on http://hg.ecmascript.org/tests/test262/raw-file/tip/LICENSE (the 

 /// "Use Terms").   Any redistribution of this code must retain the above 

 /// copyright and this notice and otherwise comply with the Use Terms.

 /**

  * This test is actually testing the [[Delete]] internal method (8.12.8). Since the

  * language provides no way to directly exercise [[Delete]], the tests are placed here.

  *

  * @path ch11/11.4/11.4.1/11.4.1-4.a-10.js

  * @description delete operator returns true for property (stringify) defined on built-in object (JSON)

  */

 function testcase() {

   try {

       var o = JSON.stringify;

 	  var desc;

 	  try {

 	  	desc = Object.getOwnPropertyDescriptor(JSON, 'stringify')

 	  } 

 	  catch (e) {

 	  };

       var d = delete JSON.stringify;

       if (d === true && JSON.stringify === undefined) {

         return true;

       }

   } finally {

     if (desc) Object.defineProperty(JSON, 'stringify', desc)

 	else JSON.stringify = o  /* this branch messes up the attributes */;

   }

  }

 runTestCase(testcase);