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+// Copyright 2012 Mozilla Corporation. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/**
+ * @description Tests that obj meets the requirements for built-in objects
+ * defined by the introduction of chapter 15 of the ECMAScript Language Specification.
+ * @param {Object} obj the object to be tested.
+ * @param {boolean} isFunction whether the specification describes obj as a function.
+ * @param {boolean} isConstructor whether the specification describes obj as a constructor.
+ * @param {String[]} properties an array with the names of the built-in properties of obj,
+ * excluding length, prototype, or properties with non-default attributes.
+ * @param {number} length for functions only: the length specified for the function
+ * or derived from the argument list.
+ * @author Norbert Lindenberg
+ */
+
+function testBuiltInObject(obj, isFunction, isConstructor, properties, length) {
+
+ if (obj === undefined) {
+ $ERROR("Object being tested is undefined.");
+ }
+
+ var objString = Object.prototype.toString.call(obj);
+ if (isFunction) {
+ if (objString !== "[object Function]") {
+ $ERROR("The [[Class]] internal property of a built-in function must be " +
+ "\"Function\", but toString() returns " + objString);
+ }
+ } else {
+ if (objString !== "[object Object]") {
+ $ERROR("The [[Class]] internal property of a built-in non-function object must be " +
+ "\"Object\", but toString() returns " + objString);
+ }
+ }
+
+ if (!Object.isExtensible(obj)) {
+ $ERROR("Built-in objects must be extensible.");
+ }
+
+ if (isFunction && Object.getPrototypeOf(obj) !== Function.prototype) {
+ $ERROR("Built-in functions must have Function.prototype as their prototype.");
+ }
+
+ if (isConstructor && Object.getPrototypeOf(obj.prototype) !== Object.prototype) {
+ $ERROR("Built-in prototype objects must have Object.prototype as their prototype.");
+ }
+
+ // verification of the absence of the [[Construct]] internal property has
+ // been moved to the end of the test
+
+ // verification of the absence of the prototype property has
+ // been moved to the end of the test
+
+ if (isFunction) {
+
+ if (typeof obj.length !== "number" || obj.length !== Math.floor(obj.length)) {
+ $ERROR("Built-in functions must have a length property with an integer value.");
+ }
+
+ if (obj.length !== length) {
+ $ERROR("Function's length property doesn't have specified value; expected " +
+ length + ", got " + obj.length + ".");
+ }
+
+ var desc = Object.getOwnPropertyDescriptor(obj, "length");
+ if (desc.writable) {
+ $ERROR("The length property of a built-in function must not be writable.");
+ }
+ if (desc.enumerable) {
+ $ERROR("The length property of a built-in function must not be enumerable.");
+ }
+ if (desc.configurable) {
+ $ERROR("The length property of a built-in function must not be configurable.");
+ }
+ }
+
+ properties.forEach(function(prop) {
+ var desc = Object.getOwnPropertyDescriptor(obj, prop);
+ if (desc === undefined) {
+ $ERROR("Missing property " + prop + ".");
+ }
+ // accessor properties don't have writable attribute
+ if (desc.hasOwnProperty("writable") && !desc.writable) {
+ $ERROR("The " + prop + " property of this built-in function must be writable.");
+ }
+ if (desc.enumerable) {
+ $ERROR("The " + prop + " property of this built-in function must not be enumerable.");
+ }
+ if (!desc.configurable) {
+ $ERROR("The " + prop + " property of this built-in function must be configurable.");
+ }
+ });
+
+ // The remaining sections have been moved to the end of the test because
+ // unbound non-constructor functions written in JavaScript cannot possibly
+ // pass them, and we still want to test JavaScript implementations as much
+ // as possible.
+
+ var exception;
+ if (isFunction && !isConstructor) {
+ // this is not a complete test for the presence of [[Construct]]:
+ // if it's absent, the exception must be thrown, but it may also
+ // be thrown if it's present and just has preconditions related to
+ // arguments or the this value that this statement doesn't meet.
+ try {
+ /*jshint newcap:false*/
+ var instance = new obj();
+ } catch (e) {
+ exception = e;
+ }
+ if (exception === undefined || exception.name !== "TypeError") {
+ $ERROR("Built-in functions that aren't constructors must throw TypeError when " +
+ "used in a \"new\" statement.");
+ }
+ }
+
+ if (isFunction && !isConstructor && obj.hasOwnProperty("prototype")) {
+ $ERROR("Built-in functions that aren't constructors must not have a prototype property.");
+ }
+
+ // passed the complete test!
+ return true;
+}
+