public function testSort()
{
$col = new MessageCollection();
$col->add(new Message('b'));
$col->add(new Message('c'));
$col->add(new Message('a'));
$this->assertEquals(array('b', 'c', 'a'), array_keys($col->all()));
$col->sort('strcasecmp');
$this->assertEquals(array('a', 'b', 'c'), array_keys($col->all()));
}
