# Introduce a new subs that can be tested.
# New subs also separates the two functionalities
# within the foreach loop.

my @filenames = parse_file_names(@file_name_list);

foreach my $file ( @filenames ) {
    if( $file =~ /go/ ) {
        populatePlaceIfExists(\%files, $file);
        @batch = ();
    }
}

sub parse_file_names {
    my @list = ();
    
    for( @_ ) {
        if ( /filename\s*=\s*(\S+)/x ) {
            push @list, $1;
        }
    }
    
    return @list;
}

sub populatePlaceIfExists {
    my $files_hash = shift;
    my $file       = shift;    
    
    if ( exists $files_hash->{$file} ) {
        push @PLACE, @batch;
        delete $files_hash->{$file};
    }
}