easejs/test/MemberBuilderValidator/GetterSetterTest.js

/**
 * Tests member builder validation rules for getters/setters
 *
 * These tests can be run in a pre-ES5 environment since they do not deal with
 * actual getters/setters; they deal only with the data associated with them.
 *
 *  Copyright (C) 2011, 2013 Mike Gerwitz
 *
 *  This file is part of GNU ease.js.
 *
 *  ease.js is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

var shared = require( __dirname + '/inc-common' );

require( 'common' ).testCase(
{
    caseSetUp: function()
    {
        var _self = this;

        this.quickFailureTest = function()
        {
            shared.quickFailureTest.apply( _self, arguments );
        };

        this.quickKeywordTest = function( keywords, identifier, prev )
        {
            shared.quickKeywordTest.call( this,
                'validateGetterSetter', keywords, identifier, prev,
                prev && { get: function() {}, set: function() {} }
            );
        };

        this.quickVisChangeTest = function( start, override, failtest, failstr )
        {
            shared.quickVisChangeTest.call( _self, start, override, failtest,
                function( name, startobj, overrideobj )
                {
                    startobj.virtual     = true;
                    overrideobj.override = true;

                    _self.sut.validateGetterSetter(
                        name, {}, overrideobj,
                        { get: function() {}, set: function() {} },
                        startobj
                    );
                },
                failstr
            );
        };
    },


    setUp: function()
    {
        var _self = this;

        // can be used to intercept warnings; redefine in test
        this.warningHandler = function( warning ) {};

        this.sut = this.require( 'MemberBuilderValidator' )(
            function( warning )
            {
                _self.warningHandler( warning );
            }
        );
    },


    /**
     * Getters/setters should not be able to override methods, for the obvious
     * reason that they are two different types and operate entirely
     * differently. Go figure.
     */
    'Cannot override method with getter or setter': function()
    {
        var name  = 'foo',
            _self = this;

        // getters and setters share the same call, so we don't need two
        // separate tests
        this.quickFailureTest( name, 'method', function()
        {
            _self.sut.validateGetterSetter(
                name, {}, {}, { member: function() {} }
            );
        } );
    },


    'Cannot override property with getter or setter': function()
    {
         var name  = 'foo',
            _self = this;

        // getters and setters share the same call, so we don't need two
        // separate tests
        this.quickFailureTest( name, 'method', function()
        {
            _self.sut.validateGetterSetter(
                name, {}, {}, { member: 'foo' }
            );
        } );
    },


    /**
     * De-escalating the visibility of any member would alter the interface of a
     * subtype, which would not be polymorphic.
     */
    'Getters/setters do not support visibility de-escalation': function()
    {
        this.quickVisChangeTest( 'public', 'protected', true );
        this.quickVisChangeTest( 'protected', 'private', true );
    },


    /**
     * Contrary to the above test, we have no such problem with visibility
     * escalation.
     */
    'Getters/setters support visibility escalation and equality': function()
    {
        var _self = this;
        shared.visEscalationTest( function( cur )
        {
            _self.quickVisChangeTest( cur[ 0 ], cur[ 1 ], false );
        } );
    },


    /**
     * See property/method tests for more information. This is not strictly
     * necessary (since getters/setters can exist only in an ES5+ environment),
     * but it's provided for consistency. It's also easy to remove this feature
     * without breaking BC. The reverse is untrue.
     */
    'Cannot redeclare private getters/setters in subtypes': function()
    {
        var _self = this;
        shared.privateNamingConflictTest( function( cur )
        {
            _self.quickVisChangeTest( cur[ 0 ], cur[ 1 ], true, 'conflict' );
        } );
    },


    /**
     * Abstract getter/setters are not yet supported. They may be supported in
     * the future. Disallowing them now will allow us to determine an
     * implementation in the future without breaking BC.
     */
    'Cannot declare abstract getters/setters': function()
    {
        this.quickKeywordTest( [ 'abstract' ], 'abstract' );
    },


    /**
     * As getters/setters are essentially methods, they are treated very
     * similarity. They cannot be declared as const. Rather, that should be
     * handled by omitting a setter.
     */
    'Cannot declare const getters/setters': function()
    {
        this.quickKeywordTest( [ 'const' ], 'const' );
    },


    /**
     * Getters/setters can be overridden just like methods, so long as they
     * follow the same keyword restrictions.
     */
    'Can override virtual getter/setter with override keyword': function()
    {
        this.quickKeywordTest( [ 'override' ], null, [ 'virtual' ] );
    },


    /**
     * The 'override' keyword must be provided if a member is being overridden.
     */
    'Must provide override keyword when overriding getter/setter': function()
    {
        this.quickKeywordTest( [], 'override', [ 'virtual' ] );
    },


    /**
     * Just like methods, getters/setters may only be overridden if they have
     * been declared 'virtual'.
     */
    'Cannot override non-virtual getter/setter': function()
    {
        this.quickKeywordTest( [ 'override' ], 'non-virtual', [] );
    },


    'Can declare getter/setter as static': function()
    {
        this.quickKeywordTest( [ 'static' ] );
    },


    /**
     * As static members cannot be overridden, it does not make sense to permit
     * the 'static' and 'virtual' keywords to be used together.
     */
    'Cannot declare getter/setter as both static and virtual': function()
    {
        this.quickKeywordTest( [ 'static', 'virtual' ], 'static' );
    },


    /**
     * If a developer uses the 'override' keyword when there is no super member
     * to override, this could hint at a number of problems (see MethodTest for
     * further discussion).
     */
    'Throws warning when using override with no super getter/setter': function()
    {
        var given = null;

        this.warningHandler = function( warning )
        {
            given = warning;
        };

        // trigger warning (override keyword with no super method)
        this.quickKeywordTest( [ 'override' ] );

        this.assertNotEqual( null, given,
            'No warning was provided'
        );

        this.assertOk( given instanceof Error,
            'Provided warning is not of type Error'
        );

        this.assertOk( ( given.message.search( shared.testName ) > -1 ),
            'Override warning should contain getter/setter name'
        );
    },
} );