easejs/test/test-interface-extend.js

/**
 * Tests extending of interfaces
 *
 *  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
 * @package test
 */

var common    = require( './common' ),
    assert    = require( 'assert' ),
    Interface = common.require( 'interface' );


( function testPropertiesNotPermittedWithinInterfaces()
{
    assert.throws( function()
    {
        Interface.extend(
        {
            // properties (non-methods) are not permitted
            prop: 'not permitted',
        });
    }, TypeError, "Properties are not permitted within Interface definitions" );
} )();


( function testGettersAndSettersNotPermittedWithinInterfaces()
{
    // don't perform this test if unsupported by environment
    if ( Object.prototype.__defineGetter__ === undefined )
    {
        return;
    }

    // so we don't break browsers that do not support getters/setters in object
    // notation
    var data = {};
    data.__defineGetter__( 'foo', function() {} );
    data.__defineSetter__( 'foo', function() {} );

    assert.throws( function()
    {
        Interface.extend( data );
    }, TypeError, "Getters/setters not permitted within Interfaces" );
} )();


assert.throws( function()
{
    Interface.extend(
    {
        // concrete method
        method: function() {}
    });
}, TypeError, "Concrete methods are not permitted within Interface definitions" );

assert.doesNotThrow(
    function()
    {
        Interface.extend(
        {
            'abstract method': [],
        });
    },
    TypeError,
    "Abstract method declarations are allowed within Interface definitions"
);


var BaseType = Interface.extend(
{
    'abstract method': [],
});

assert.ok(
    ( BaseType.prototype.method instanceof Function ),
    "Interface contains defined abstract methods"
);


var SubType = Interface.extend( BaseType,
{
    'abstract second': [],
});

assert.ok(
    ( SubType.prototype instanceof BaseType ),
    "Generic interface extend method can extend from other interfaces"
);

assert.ok(
    ( SubType.prototype.method === BaseType.prototype.method ),
    "Interface subtypes inherit abstract methods"
);

assert.ok(
    ( SubType.prototype.second instanceof Function ),
    "Interfaces can be extended with additional abstract methods"
);


assert.ok(
    ( BaseType.extend instanceof Function ),
    "Interface contains extend method"
);


var SubType2 = BaseType.extend(
{
    'abstract second': [],
});

assert.ok(
    ( SubType2.prototype instanceof BaseType ),
    "Interface extend method can extend interfaces"
);

assert.ok(
    ( SubType2.prototype.second instanceof Function ),
    "Interfaces can be extended with additional abstract methods using " +
        "shorthand extend method"
);