Perl functional tests

I have a package MyImage.pm in which there is a function. I need to write tests for this function.

sub get_image_info {
    my ($file_name) = @_;
    return ('', 0, 0) unless -e $file_name;
    my @type   = split /\./, $file_name;
    my $image  = GD::Image->new($file_name);
    my $width  = $image->width;
    my $height = $image->height;
    return ($type[-1], $width, $height);
}

1;

use v5.30;
use warnings;
use Test::More;
use MyImage;
BEGIN {use_ok('MyImage', qw( get_image_info)); }

    subtest 'get_image_info' => sub {
        
    my $file_name = "aaa" ;
     is(get_image_info($file_name), , "aaa");

};

done_testing();