JSTests/test262/test/built-ins/Object/defineProperty/15.2.3.6-4-12.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 non-configurable properties, step 9a of
    [[DefineOwnProperty]] rejects changing the kind of a property.
es5id: 15.2.3.6-4-12
description: >
    Object.defineProperty throws TypeError when changing
    non-configurable data properties to accessor properties
---*/

  var o = {};

  // create a data valued property; all other attributes default to false.
  var d1 = { value: 101, configurable: false };
  Object.defineProperty(o, "foo", d1);

  // changing "foo" to be an accessor should fail, since [[Configurable]]
  // on the original property will be false.

  // dummy getter
  var getter = function () { return 1; }

  var desc = { get: getter };
assert.throws(TypeError, function() {
    Object.defineProperty(o, "foo", desc);
});
      // the property should remain a data valued property.
      var d2 = Object.getOwnPropertyDescriptor(o, "foo");
assert.sameValue(d2.value, 101, 'd2.value');
assert.sameValue(d2.writable, false, 'd2.writable');
assert.sameValue(d2.enumerable, false, 'd2.enumerable');
assert.sameValue(d2.configurable, false, 'd2.configurable');