The Tor Browser / file revision

 /*

  * Any copyright is dedicated to the Public Domain.

  * http://creativecommons.org/licenses/publicdomain/

  */

 //-----------------------------------------------------------------------------

 var BUGNUMBER = 537863;

 var summary =

   'undefined, Infinity, and NaN global properties should not be writable';

 print(BUGNUMBER + ": " + summary);

 /**************

  * BEGIN TEST *

  **************/

 var desc, old, error;

 var global = this;

 var names = ["NaN", "Infinity", "undefined"];

 for (var i = 0; i < names.length; i++)

 {

   var name = names[i];

   desc = Object.getOwnPropertyDescriptor(global, name);

   assertEq(desc !== undefined, true, name + " should be present");

   assertEq(desc.enumerable, false, name + " should not be enumerable");

   assertEq(desc.configurable, false, name + " should not be configurable");

   assertEq(desc.writable, false, name + " should not be writable");

   old = global[name];

   global[name] = 17;

   assertEq(global[name], old, name + " changed on setting?");

   error = "before";

   try

   {

     throw new TypeError("SpiderMonkey doesn't currently implement " +

                         "strict-mode throwing when setting a readonly " +

                         "property, not running this bit of test for now; " +

                         "see bug 537873");

     (function() { "use strict"; global[name] = 42; error = "didn't throw"; })();

   }

   catch (e)

   {

     if (e instanceof TypeError)

       error = "typeerror";

     else

       error = "bad exception: " + e;

   }

   assertEq(error, "typeerror", "wrong strict mode error setting " + name);

 }

 /******************************************************************************/

 reportCompare(true, true);

 print("All tests passed!");