easejs/test/test-class_builder-visibility.js

/**
 * Tests class builder visibility implementation
 *
 * See also: test-class-visibility.js
 *
 *  Copyright (C) 2010 Mike Gerwitz
 *
 *  This file is part of ease.js.
 *
 *  ease.js is free software: you can redistribute it and/or modify it under the
 *  terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation, either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author  Mike Gerwitz
 */

var common  = require( './common' ),
    assert  = require( 'assert' ),
    util    = common.require( 'util' ),

    // XXX: get rid of this disgusting mess; we're mid-refactor and all these
    // dependencies should not be necessary for testing
    ClassBuilder         = common.require( '/ClassBuilder' ),
    MethodWrapperFactory = common.require( '/MethodWrapperFactory' ),
    wrappers             = common.require( '/MethodWrappers' ).standard
;


require( 'common' ).testCase(
{
    setUp: function()
    {
        this.builder = ClassBuilder(
            this.require( '/MemberBuilder' )(
                MethodWrapperFactory( wrappers.wrapNew ),
                MethodWrapperFactory( wrappers.wrapOverride ),
                this.getMock( 'MemberBuilderValidator' )
            ),
            this.require( '/VisibilityObjectFactoryFactory' ).fromEnvironment()
        );
    },


    /**
     * As discussed in GH#15, there's a bit of an issue when passing around
     * 'this' from within a method. For example, passing 'this' as an argument
     * or invoking a method with it as the context will effectively defeat
     * encapsulation.  Unfortunately, there's really no way around that. Maybe a
     * more elegant solution will arise in the future. For now, not likely.
     *
     * We need to provide a means to reference the actual instance. __inst is
     * that solution.
     */
    'Self property references instance rather than property object': function()
    {
        var result = null,
            ref    = null,

            foo = this.builder.build( {
                'public __construct': function()
                {
                    // rather than returning, assign to external var so that we can
                    // rest assured that the return value wasn't manipulated
                    result = this.__inst;
                    ref    = this;
                }
            } )();

        this.assertDeepEqual( result, foo,
            "this.__inst returns reference to actual instance"
        );

        // the property should be read-only
        if ( util.definePropertyFallback() === false )
        {
            assert.equal(
                Object.getOwnPropertyDescriptor( ref, '__inst' ).writable,
                false,
                "this.__inst is not writable"
            );
        }
    },
} );