I would write this a little differently to guard against a directory that has lots of files. The below example iterates over the directory handle instead of adding the directory filenames to an array. I also added more error checking to give a tighter example.

use strict;
use warnings;

my $testfolder = './test';

my @newfiles;

if ( opendir(my $dir, $testfolder) ) {

    while ( my $file = readdir($dir) ) {

        # skip parent and current directories
        next              if ($file eq '.' || $file eq '..');
        
        # skip directories
        next              if (-d $file);                      

        # create the fullpath
        my $full_pathname = $testfolder . "/" . $file;        
        next              unless (-e $full_pathname);         
        
        # get the filesize
        my $filesize      = -s $full_pathname;                
        
        # push the non-zero sized file to the new file array
        if ($filesize) {
            push(@newfiles,$file);                            
        }
        
    }
    
    closedir($dir);
    
} else {

    die "[Error] UNABLE TO OPEN DIRECTORY: [$!]";

}

foreach my $file (@newfiles) {
    print "$file\n";
}
[download]