js/src/tests/supporting/testBuiltInObject.js@6474c204b198
js/src/tests/supporting/testBuiltInObject.js
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
1 // Copyright 2012 Mozilla Corporation. All rights reserved.
2 // This code is governed by the BSD license found in the LICENSE file.
4 /**
5 * @description Tests that obj meets the requirements for built-in objects
6 * defined by the introduction of chapter 15 of the ECMAScript Language Specification.
7 * @param {Object} obj the object to be tested.
8 * @param {boolean} isFunction whether the specification describes obj as a function.
9 * @param {boolean} isConstructor whether the specification describes obj as a constructor.
10 * @param {String[]} properties an array with the names of the built-in properties of obj,
11 * excluding length, prototype, or properties with non-default attributes.
12 * @param {number} length for functions only: the length specified for the function
13 * or derived from the argument list.
14 * @author Norbert Lindenberg
15 */
17 function testBuiltInObject(obj, isFunction, isConstructor, properties, length) {
19 if (obj === undefined) {
20 $ERROR("Object being tested is undefined.");
21 }
23 var objString = Object.prototype.toString.call(obj);
24 if (isFunction) {
25 if (objString !== "[object Function]") {
26 $ERROR("The [[Class]] internal property of a built-in function must be " +
27 "\"Function\", but toString() returns " + objString);
28 }
29 } else {
30 if (objString !== "[object Object]") {
31 $ERROR("The [[Class]] internal property of a built-in non-function object must be " +
32 "\"Object\", but toString() returns " + objString);
33 }
34 }
36 if (!Object.isExtensible(obj)) {
37 $ERROR("Built-in objects must be extensible.");
38 }
40 if (isFunction && Object.getPrototypeOf(obj) !== Function.prototype) {
41 $ERROR("Built-in functions must have Function.prototype as their prototype.");
42 }
44 if (isConstructor && Object.getPrototypeOf(obj.prototype) !== Object.prototype) {
45 $ERROR("Built-in prototype objects must have Object.prototype as their prototype.");
46 }
48 // verification of the absence of the [[Construct]] internal property has
49 // been moved to the end of the test
51 // verification of the absence of the prototype property has
52 // been moved to the end of the test
54 if (isFunction) {
56 if (typeof obj.length !== "number" || obj.length !== Math.floor(obj.length)) {
57 $ERROR("Built-in functions must have a length property with an integer value.");
58 }
60 if (obj.length !== length) {
61 $ERROR("Function's length property doesn't have specified value; expected " +
62 length + ", got " + obj.length + ".");
63 }
65 var desc = Object.getOwnPropertyDescriptor(obj, "length");
66 if (desc.writable) {
67 $ERROR("The length property of a built-in function must not be writable.");
68 }
69 if (desc.enumerable) {
70 $ERROR("The length property of a built-in function must not be enumerable.");
71 }
72 if (desc.configurable) {
73 $ERROR("The length property of a built-in function must not be configurable.");
74 }
75 }
77 properties.forEach(function(prop) {
78 var desc = Object.getOwnPropertyDescriptor(obj, prop);
79 if (desc === undefined) {
80 $ERROR("Missing property " + prop + ".");
81 }
82 // accessor properties don't have writable attribute
83 if (desc.hasOwnProperty("writable") && !desc.writable) {
84 $ERROR("The " + prop + " property of this built-in function must be writable.");
85 }
86 if (desc.enumerable) {
87 $ERROR("The " + prop + " property of this built-in function must not be enumerable.");
88 }
89 if (!desc.configurable) {
90 $ERROR("The " + prop + " property of this built-in function must be configurable.");
91 }
92 });
94 // The remaining sections have been moved to the end of the test because
95 // unbound non-constructor functions written in JavaScript cannot possibly
96 // pass them, and we still want to test JavaScript implementations as much
97 // as possible.
99 var exception;
100 if (isFunction && !isConstructor) {
101 // this is not a complete test for the presence of [[Construct]]:
102 // if it's absent, the exception must be thrown, but it may also
103 // be thrown if it's present and just has preconditions related to
104 // arguments or the this value that this statement doesn't meet.
105 try {
106 /*jshint newcap:false*/
107 var instance = new obj();
108 } catch (e) {
109 exception = e;
110 }
111 if (exception === undefined || exception.name !== "TypeError") {
112 $ERROR("Built-in functions that aren't constructors must throw TypeError when " +
113 "used in a \"new\" statement.");
114 }
115 }
117 if (isFunction && !isConstructor && obj.hasOwnProperty("prototype")) {
118 $ERROR("Built-in functions that aren't constructors must not have a prototype property.");
119 }
121 // passed the complete test!
122 return true;
123 }
