test262/test/built-ins/Object/defineProperty/15.2.3.6-4-6.js

// 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.

/*---
info: >
    Step 4 of defineProperty calls the [[DefineOwnProperty]] internal method
    of O to define the property. Step 6 of [[DefineOwnProperty]] returns if
    every field of desc also occurs in current and every field in desc has
    the same value as current.
es5id: 15.2.3.6-4-6
description: >
    Object.defineProperty is no-op if current and desc are the same
    accessor desc
includes: [runTestCase.js]
---*/

function testcase() {
  function sameAccessorDescriptorValues(d1, d2) {
    return (d1.get == d2.get &&
            d1.enumerable == d2.enumerable &&
            d1.configurable == d2.configurable);
  }

  var o = {};

  // create an accessor property with the following attributes:
  // enumerable: true, configurable: true
  var desc = {
               get: function () {},
               enumerable: true,
               configurable: true
             };

  Object.defineProperty(o, "foo", desc);

  // query for, and save, the desc. A subsequent call to defineProperty
  // with the same desc should not disturb the property definition.
  var d1 = Object.getOwnPropertyDescriptor(o, "foo");  

  // now, redefine the property with the same descriptor
  // the property defintion should not get disturbed.
  Object.defineProperty(o, "foo", desc);

  var d2 = Object.getOwnPropertyDescriptor(o, "foo"); 

  if (sameAccessorDescriptorValues(d1, d2) === true) {
    return true;
  }
 }
runTestCase(testcase);