module Main exposing (..)

import ElmTest exposing (..)
import Hamming exposing (distance)


tests : Test
tests =
  suite
    "Hamming"
    [ test
        "identical strands"
        (assertEqual (Just 0) (distance "A" "A"))
    , test
        "long identical strands"
        (assertEqual (Just 0) (distance "GGACTGA" "GGACTGA"))
    , test
        "complete distance in single nucleotide strands"
        (assertEqual (Just 1) (distance "A" "G"))
    , test
        "complete distance in small strands"
        (assertEqual (Just 2) (distance "AG" "CT"))
    , test
        "small distance in small strands"
        (assertEqual (Just 1) (distance "AT" "CT"))
    , test
        "small distance"
        (assertEqual (Just 1) (distance "GGACG" "GGTCG"))
    , test
        "small distance in long strands"
        (assertEqual (Just 2) (distance "ACCAGGG" "ACTATGG"))
    , test
        "non-unique character in first strand"
        (assertEqual (Just 1) (distance "AGA" "AGG"))
    , test
        "non-unique character in second strand"
        (assertEqual (Just 1) (distance "AGG" "AGA"))
    , test
        "large distance"
        (assertEqual (Just 4) (distance "GATACA" "GCATAA"))
    , test
        "large distance in off-by-one strand"
        (assertEqual (Just 9) (distance "GGACGGATTCTG" "AGGACGGATTCT"))
    , test
        "empty strands"
        (assertEqual (Just 0) (distance "" ""))
    , test
        "disallow first strand longer"
        (assertEqual Nothing (distance "AATG" "AAA"))
    , test
        "disallow second strand longer"
        (assertEqual Nothing (distance "ATA" "AGTG"))
    ]


main : Program Never
main =
  runSuite tests