mirror of https://github.com/tc39/test262.git
59 lines
1.8 KiB
JavaScript
59 lines
1.8 KiB
JavaScript
// Copyright 2012 Mozilla Corporation. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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description: |
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A function used to assert the correctness of built-in objects.
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---*/
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/**
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* @description Tests that obj meets the requirements for built-in objects
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* defined by the introduction of chapter 15 of the ECMAScript Language Specification.
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* @param {Object} obj the object to be tested.
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* @author Norbert Lindenberg
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*/
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function testBuiltInObject(obj) {
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if (obj === undefined) {
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$ERROR("Object being tested is undefined.");
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}
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var objString = Object.prototype.toString.call(obj);
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if (objString !== "[object Function]") {
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$ERROR("The [[Class]] internal property of a built-in function must be " +
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"\"Function\", but toString() returns " + objString);
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}
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if (!Object.isExtensible(obj)) {
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$ERROR("Built-in objects must be extensible.");
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}
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if (Object.getPrototypeOf(obj) !== Function.prototype) {
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$ERROR("Built-in functions must have Function.prototype as their prototype.");
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}
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var exception;
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// this is not a complete test for the presence of [[Construct]]:
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// if it's absent, the exception must be thrown, but it may also
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// be thrown if it's present and just has preconditions related to
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// arguments or the this value that this statement doesn't meet.
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try {
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/*jshint newcap:false*/
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var instance = new obj();
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} catch (e) {
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exception = e;
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}
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if (exception === undefined || exception.name !== "TypeError") {
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$ERROR("Built-in functions that aren't constructors must throw TypeError when " +
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"used in a \"new\" statement.");
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}
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if (obj.hasOwnProperty("prototype")) {
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$ERROR("Built-in functions that aren't constructors must not have a prototype property.");
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}
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// passed the complete test!
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return true;
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}
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