exercise: Hamming
version: 3
plan: 15
tests: |-
  for $c-data<cases>.values {
    if .<expected><error> {
      throws-like {hamming-distance(|.<strand1 strand2>)}, Exception, .<description>;
    } else {
      is hamming-distance(|.<strand1 strand2>), |.<expected description>;
    }
  }

unit: module
example: |-
  sub hamming-distance (
    +@strands where { .elems == 2 && [==] $_».chars } --> Int:D
  ) is export {
    sum [Zne] @strands».comb
  }
stub: |-
  sub hamming-distance ($strand1, $strand2) is export {
  }