JSTests/test262/test/built-ins/Object/defineProperty/15.2.3.6-4-18.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 11.a.i
    of [[DefineOwnProperty]] rejects changing the setter if present.
es5id: 15.2.3.6-4-18
description: >
    Object.defineProperty throws TypeError when changing setter of
    non-configurable accessor properties(8.12.9 step 11.a.i)
---*/

  var o = {};

  // create an accessor property; all other attributes default to false.
  // dummy getter
  var getter = function () { return 1;}
  var d1 = { get: getter };
  Object.defineProperty(o, "foo", d1);

  // now, trying to change the setter should fail, since [[Configurable]]
  // on the original property will be false.
  var setter = function (x) {};
  var desc = { set: setter };
assert.throws(TypeError, function() {
    Object.defineProperty(o, "foo", desc);
});
      // the property should remain unchanged.
      var d2 = Object.getOwnPropertyDescriptor(o, "foo");
assert.sameValue(d2.get, getter, 'd2.get');
assert.sameValue(d2.configurable, false, 'd2.configurable');
assert.sameValue(d2.enumerable, false, 'd2.enumerable');