Property {
  ##[ x <- Int #]##
  square( $x ) == $x * $x;
}, name => "Finding \$x's square";

##</code><code>##

use Test::Differences;
Property {
  ##[ x <- Int, y <- Int #]##
  my @expected = map { $x * $_ } 0 .. $y; # Or something ...
  my @result = getDataAsArray( $x, $y );

  eq_or_diff( \@result, \@expected );
}, name => "Transmogrifer parameters ok";