LayoutTests/ietestcenter/Javascript/TestCases/15.2.3.6-4-5.js

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/*
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.
*/

ES5Harness.registerTest( {
id: "15.2.3.6-4-5",

path: "TestCases/chapter15/15.2/15.2.3/15.2.3.6/15.2.3.6-4-5.js",

description: "Object.defineProperty is no-op if current and desc are the same data desc",

test: function testcase() {
  function sameDataDescriptorValues(d1, d2) {
    return (d1.value === d2.value &&
            d1.enumerable === d2.enumerable &&
            d1.writable === d2.writable &&
            d1.configurable === d2.configurable);
  }

  var o = {};

  // create a data valued property with the following attributes:
  // value: 101, enumerable: true, writable: true, configurable: true
  o["foo"] = 101;

  // 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.
  var desc = { value: 101, enumerable: true, writable: true, configurable: true };
  Object.defineProperty(o, "foo", desc);

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

  if (sameDataDescriptorValues(d1, d2) === true) {
    return true;
  }
 },

precondition: function prereq() {
  return fnExists(Object.defineProperty) && fnExists(Object.getOwnPropertyDescriptor);
 }
});