public function testStackOutput()
{
$this->assertEquals((string) FA::s(), '<span class="fa-stack"></span>');
$this->assertEquals((string) FA::stack(), '<span class="fa-stack"></span>');
$this->assertEquals((string) FA::stack()->tag('div'), '<div class="fa-stack"></div>');
$this->assertEquals((string) FA::stack()->icon('cog'), '<span class="fa-stack"><i class="fa fa-cog fa-stack-1x"></i></span>');
$this->assertEquals((string) FA::stack()->on('square-o'), '<span class="fa-stack"><i class="fa fa-square-o fa-stack-2x"></i></span>');
$this->assertEquals((string) FA::stack()->icon('cog')->on('square-o'), '<span class="fa-stack"><i class="fa fa-square-o fa-stack-2x"></i><i class="fa fa-cog fa-stack-1x"></i></span>');
$this->assertEquals((string) FA::stack(['data-role' => 'stack'])->icon('cog', ['data-role' => 'icon'])->on('square-o', ['data-role' => 'background']), '<span class="fa-stack" data-role="stack"><i class="fa fa-square-o fa-stack-2x" data-role="background"></i><i class="fa fa-cog fa-stack-1x" data-role="icon"></i></span>');
$this->assertEquals((string) FA::stack()->icon((new Icon('cog'))->spin())->on((new Icon('square-o'))->size(FA::SIZE_3X)), '<span class="fa-stack"><i class="fa fa-square-o fa-3x fa-stack-2x"></i><i class="fa fa-cog fa-spin fa-stack-1x"></i></span>');
$this->assertEquals((string) FA::stack()->icon(FA::Icon('cog')->spin())->on(FA::Icon('square-o')->size(FA::SIZE_3X)), '<span class="fa-stack"><i class="fa fa-square-o fa-3x fa-stack-2x"></i><i class="fa fa-cog fa-spin fa-stack-1x"></i></span>');
$this->assertNotEquals((string) FA::stack()->icon((string) FA::Icon('cog')->spin())->on((string) FA::Icon('square-o')->size(FA::SIZE_3X)), '<span class="fa-stack"><i class="fa fa-square-o fa-3x fa-stack-2x"></i><i class="fa fa-cog fa-spin fa-stack-1x"></i></span>');
}
