exercise: Grains
version: 1
plan: 13
imports: '&grains-on-square &total-grains'
tests: |-
  for @($c-data<cases>[0]<cases>) {
    if .<expected> == -1 {
      throws-like { grains-on-square(.<input>) }, Exception, .<description>;
    } else {
      is grains-on-square(.<input>), |.<expected description>;
    }
  }
  is total-grains, |$c-data<cases>[1]<expected description>;

unit: module
example: |-
  sub grains-on-square ($number) is export {
    die if $number < 1 or $number > 64;
    2**($number-1);
  }

  sub total-grains is export {
    my Int $total;
    for  1..64 { $total += grains-on-square($_) }
    $total;
  }