public function testFlatten()
{
$input = array('a', 'b', 'c', 'd', array('first' => 'e', 'f', 'second' => 'g', array('h', 'third' => 'i', array(array(array(array('j', 'k', 'l')))))));
$expectNoKeys = range('a', 'l');
$expectWithKeys = array('a', 'b', 'c', 'd', 'first' => 'e', 'f', 'second' => 'g', 'h', 'third' => 'i', 'j', 'k', 'l');
is($expectWithKeys, Arr::flat($input));
is($expectNoKeys, Arr::flat($input, false));
is($expectWithKeys, Arr::flat($input, true));
}