public function testChecksum()
{
// checksum of empty image
$sum = '40cd750bba9870f18aada2478b24840a';
$img = new ImageCache();
$this->assertEquals($sum, $img->checksum());
// checksum of test image resized to 300x200
$sum = '792dcbdcefdd977a099b6fdd06c8ab57';
$img = new ImageCache();
$img->open('foo/bar.jpg');
$img->resize(300, 200);
$this->assertEquals($sum, $img->checksum());
}
