JSTests/test262/test/built-ins/Object/defineProperty/15.2.3.6-4-14.js

// Copyright (c) 2012 Ecma International.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
info: |
    Step 4 of defineProperty calls the [[DefineOwnProperty]] internal method
    of O to define the property. For configurable properties, step 9b of
    [[DefineOwnProperty]] permits changing the kind of a property.
es5id: 15.2.3.6-4-14
description: >
    Object.defineProperty permits changing data property to accessor
    property for configurable properties
---*/

  var o = {};

  // create a data property. In this case,
  // [[Enumerable]] and [[Configurable]] are true
  o["foo"] = 101;

  // changing "foo" to be an accessor should succeed, since [[Configurable]]
  // on the original property will be true. Existing values of [[Configurable]]
  // and [[Enumerable]] need to be preserved and the rest need to be set to
  // their default values

  // dummy getter
  var getter = function () { return 1; }
  var d1 = { get: getter };
  Object.defineProperty(o, "foo", d1);

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

assert.sameValue(d2.get, getter, 'd2.get');
assert.sameValue(d2.enumerable, true, 'd2.enumerable');
assert.sameValue(d2.configurable, true, 'd2.configurable');