#!perl -T

use 5.032;
use warnings;
...
my @prefixes = qw{...};
my @suffixes = glob '{,x}{,y}{,z}';
...
for my $prefix (@prefixes) {
    for my $suffix (@suffixes) {
        my $name = join '_', $prefix, split //, $suffix;
        # run is(...) test with $name here
    }
}