London Code Dojo 34

dojo.erl

-module(dojo).
-import(lists,[nth/2,split/2,delete/2]).
-compile([export_all]).

deck() ->
    [ {Rank, Suit} || Suit <- [hearts, spades, clubs, diamonds] , Rank <- [ace, king, queen, jack, 10, 9 ,8 ,7 , 6, 5 ,4 ,3 ,2] ].

shuffle([]) ->
    [];
shuffle(Xs) ->
    Elem = nth(rand:uniform(length(Xs)), Xs),
    [Elem | shuffle(delete(Elem, Xs))].

split_all([N | Ns], Xs) ->
    {First , Rest} = split(N, Xs),
    [First | split_all(Ns, Rest)];
split_all(_, Xs) ->
    [Xs].

deal(Deck) ->
    list_to_tuple(split_all([1,2,3,4,5,6,7,1], Deck) ++ [[]] ++ [[]] ++ [[]] ++ [[]]).

move(From, To, Board) ->
    [F | R] = element(From, Board),
    Dest = element(To, Board),
    D1 = setelement(To, Board, [F | Dest]),
    setelement(From, D1, R).

dojo_tests.erl

-module(dojo_tests).
-include_lib("eunit/include/eunit.hrl").

deck_has_52_cards_test() ->
    ?assert(52 == length(dojo:deck())).

deck_can_be_shuffled_test() ->
    Unshuffled_deck = dojo:deck(),
    Shuffled_deck = dojo:shuffle(dojo:deck()),
    ?assert(Unshuffled_deck =/= Shuffled_deck).

shuffled_deck_still_has_52_cards_test() ->
    ?assert(52 == length(dojo:shuffle(dojo:deck()))).

deal_creates_13_piles_test() ->
    ?assert(13 == tuple_size(dojo:deal(dojo:deck()))).

can_put_ace_on_empty_destination_slot_test() ->
    Start_State = dojo:deal(dojo:deck()),
    Game = dojo:move(1, 13, Start_State),
    ?assert(0 == length(element(1, Game))),
    ?assert(1 == length(element(13, Game))).

%% can_not_put_non_ace_on_empty_destination_slot_test() ->
%%     Start_State = dojo:deal(dojo:deck()),
%%     Game = dojo:move(2, 13, Start_State),
%%     ?assert(2 == length(element(2, Game))),
%%     ?assert(0 == length(element(13, Game))).