src/third_party/mozjs-45/js/src/tests/ecma_5/Array/length-truncate-nonconfigurable.js

/*
 * Any copyright is dedicated to the Public Domain.
 * http://creativecommons.org/licenses/publicdomain/
 * Contributor:
 *   Jeff Walden <jwalden+code@mit.edu>
 */

//-----------------------------------------------------------------------------
var BUGNUMBER = 858381;
var summary =
  "Array length redefinition behavior with non-configurable elements";

print(BUGNUMBER + ": " + summary);

/**************
 * BEGIN TEST *
 **************/

var arr = [0, 1, 2];
Object.defineProperty(arr, 1, { configurable: false });

try
{
  Object.defineProperty(arr, "length", { value: 0, writable: false });
}
catch (e)
{
  assertEq(e instanceof TypeError, true,
           "must throw TypeError when array truncation would have to remove " +
           "non-configurable elements");
}

assertEq(arr.length, 2, "length is highest remaining index plus one");

var desc = Object.getOwnPropertyDescriptor(arr, "length");
assertEq(desc !== undefined, true);

assertEq(desc.value, 2);
assertEq(desc.writable, false);
assertEq(desc.enumerable, false);
assertEq(desc.configurable, false);

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

if (typeof reportCompare === "function")
  reportCompare(true, true);

print("Tests complete");