137 lines
3.8 KiB
JavaScript
137 lines
3.8 KiB
JavaScript
/**
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* Tests util.getPropertyDescriptor
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*
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* Copyright (C) 2010 Mike Gerwitz
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*
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* This file is part of ease.js.
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*
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* ease.js is free software: you can redistribute it and/or modify it under the
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* terms of the GNU Lesser General Public License as published by the Free
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* Software Foundation, either version 3 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
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* for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* @author Mike Gerwitz
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*/
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var common = require( './common' ),
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assert = require( 'assert' ),
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util = common.require( 'util' ),
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get_set = !( util.definePropertyFallback() )
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;
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/**
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* If Object.getOwnPropertyDescriptor is provided by our environment, it should
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* be used by util
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*/
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( function testUtilGetOwnPropertyDescriptorIsObjectsIfAvailable()
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{
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if ( get_set && Object.getOwnPropertyDescriptor )
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{
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assert.strictEqual(
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util.getOwnPropertyDescriptor,
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Object.getOwnPropertyDescriptor,
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"Util should use Object.getOwnPropertyDescriptor if available"
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);
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}
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} )();
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/**
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* The function should provide a boolean value indicating whether it can
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* traverse the prototype chain
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*/
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( function testIndicatesWhetherTraversalIsPossible()
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{
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var traversable = ( {}.__proto__ ) ? true : false;
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assert.equal( util.getPropertyDescriptor.canTraverse, traversable,
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"Indicates whether traversal is possible"
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);
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} )();
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/**
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* We don't want tricksters to get funky with our system
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*/
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( function testTraversablePropertyIsNonWritable()
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{
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var getDesc;
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if ( get_set )
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{
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assert.equal(
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Object.getOwnPropertyDescriptor(
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util.getPropertyDescriptor, 'canTraverse'
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).writable,
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false,
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"Should not be able to alter canTravese value"
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);
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}
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} )();
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/**
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* The return value should mimic Object.getOwnPropertyDescriptor() if we're not
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* having to traverse the prototype chain
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*/
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( function testActsExactlyAsGetOwnPropertyDescriptorInEs5SystemsOnSameObject()
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{
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var obj = { foo: 'bar' },
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desc1 = util.getOwnPropertyDescriptor( obj, 'foo' ),
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desc2 = util.getPropertyDescriptor( obj, 'foo' )
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;
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assert.deepEqual( desc1, desc2,
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"When operating one level deep, should return same as " +
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"Object.getOwnPropertyDescriptor"
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);
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} )();
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/**
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* If we *do* have to start traversing the prototype chain (which
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* Object.getOwnPropertyDescriptor() cannot do), then it should be as if we
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* called Object.getOwnPropertyDescriptor() on the object in the prototype chain
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* containing the requested property.
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*/
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( function testTraversesThePrototypeChain()
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{
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// if we cannot traverse the prototype chain, this test is pointless
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if ( !util.getPropertyDescriptor.canTraverse )
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{
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return;
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}
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var proto = { foo: 'bar' },
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obj = function() {}
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;
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obj.prototype = proto;
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// to give ourselves the prototype chain (we don't want to set __proto__
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// because this test will also be run on pre-ES5 engines)
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var inst = new obj(),
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// get the actual descriptor
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expected = util.getOwnPropertyDescriptor( proto, 'foo' ),
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// attempt to gather the descriptor from the prototype chain
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given = util.getPropertyDescriptor( inst, 'foo' )
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;
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assert.deepEqual( given, expected,
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"Properly traverses the prototype chain to retrieve the descriptor"
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);
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} )();
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