PerlMagick: Transform may not work

Hi,

I trying to use PerlMagick to rotate an image from his center.
Therefore I want to use the "transform" function - unfortunatley  
nothing happens.
Below my sample.

Thx Alex

use strict;
use Image::Magick;

my $file = $ARGV[0] || die "Missing input file\n";

my $test = Image::Magick->new();
$test->Set(density => '150');
$test->Read($file);

$test->Transform(rotate=>'5', gravity=>'Center');

$test->Write('rot-'. $file);
	
exit 0;