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easejs/test/Util/GlobalTest.js

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/**
* Tests global scope handling
*
* Copyright (C) 2014 Free Software Foundation, Inc.
*
* 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 _global = this;
require( 'common' ).testCase(
{
caseSetUp: function()
{
this.Sut = this.require( 'util/Global' );
this.gobj = this.Sut.expose();
this.uniq = '___$$easejs$globaltest$$';
},
/**
* Check common environments and ensure that the returned object is
* strictly equal to the global object for that environment. For
* environments that we do *not* know about, just check for a common
* object that must exist in ES3 and above.
*/
'Global object represents environment global object': function()
{
switch ( true )
{
// browser
case _global.window:
this.assertStrictEqual( this.gobj, _global.window );
break;
// Node.js
case _global.root:
this.assertStrictEqual( this.gobj, _global.root );
break;
// something else; we'll just check for something that should
// exist in >=ES3
default:
this.assertStrictEqual( this.gobj.Array, Array );
}
},
/**
* Since ease.js makes use of ECMAScript features when they are
* available, it must also find a way to gracefully degrade to support
* less fortunate environments; the ability to define alternative
* definitions is key to that.
*/
'Providing alternative will set value if name does not exist':
function()
{
var sut = this.Sut();
var field = this.uniq,
value = { _: 'easejsOK' };
sut.provideAlt( field, function() { return value; } );
this.assertStrictEqual( sut.get( field ), value );
},
/**
* It is also important that our own definitions do not pollute the
* global scope; reasons for this are not just to be polite, but also
* because other code/libraries may provide their own definitions that
* we would not want to interfere with. (Indeed, we'd also want to use
* those definitions, if they already exist before provideAlt is
* called.)
*/
'Providing alternative will not pollute the global scope': function()
{
this.Sut().provideAlt( this.uniq, function() { return {} } );
this.assertEqual( this.gobj[ this.uniq ], undefined );
},
/**
* Our alternatives are unneeded if the object we are providing an
* alternative for is already defined.
*/
'Providing alternative will not modify global if name exists':
function()
{
var sut = this.Sut();
// a field that must exist in ES3+
var field = 'Array',
orig = this.gobj[ field ];
sut.provideAlt( field, function() { return {}; } );
this.assertStrictEqual( sut.get( field ), orig );
},
/**
* Once an alternative is defined, it shall be treated as though the
* value were defined globally; providing additional alternatives should
* therefore have no effect.
*/
'Providing alternative twice will not modify first alternative':
function()
{
var sut = this.Sut();
field = this.uniq,
expected = { _: 'easejsOK' };
// first should provide alternative, second should do nothing
sut.provideAlt( field, function() { return expected; } );
sut.provideAlt( field, function() { return 'oops'; } );
this.assertStrictEqual( sut.get( field ), expected );
},
'provideAlt returns self for method chaining': function()
{
var sut = this.Sut();
this.assertStrictEqual( sut,
sut.provideAlt( 'foo', function() {} )
);
},
} );