-module(zlists_tests).
-compile(export_all).
-import(zlists, [list_to_zlist/1, zlist_to_list/1,
                 prev/1, next/1, current/1,
                 replace/2, insert/2, delete/1,
                 map/2, rmap/2]).
-include_lib("eunit/include/eunit.hrl").

list_to_zlist_test_() -> % Dialyzer will warn about improper lists.
    [?_assertEqual({[], []}, list_to_zlist([])),
     ?_assertEqual({[], [a]}, list_to_zlist([a])),
     ?_assertEqual({[], [a,b,c]}, list_to_zlist([a,b,c]))].

zlist_to_list_test_() ->
    [?_assertEqual([], zlist_to_list({[], []})),
     ?_assertEqual([a], zlist_to_list({[a], []})),
     ?_assertEqual([a], zlist_to_list({[], [a]})),
     ?_assertEqual([a,b], zlist_to_list({[a], [b]})),
     ?_assertEqual([a,b,c,d], zlist_to_list({[b,a], [c,d]}))].

prev_test_() ->
    [?_assertError(function_clause, prev({[],[1,2,3]})),
     ?_assertEqual({[1], [2,3,4]}, prev({[2,1], [3,4]}))].

next_test_() ->
    [?_assertError(function_clause, next({[1,2,3],[]})),
     ?_assertEqual({[2,1], [3,4]}, next({[1], [2,3,4]}))].

current_test_() ->
    [?_assertError(function_clause, current({[], []})),
     ?_assertError(function_clause, current({[1], []})),
     ?_assertEqual(2, current({[1], [2,3]}))].

replace_test_() ->
    [?_assertError(function_clause, replace(1, {[a], []})),
     ?_assertEqual({[], [3,2]}, replace(3, {[], [1,2]}))].

insert_test_() ->
   [?_assertEqual({[],[1]}, insert(1, {[], []})),
    ?_assertEqual({[1], [2,3,4]}, insert(2, {[1], [3,4]}))].

delete_test_() ->
    [?_assertError(function_clause, delete({[], []})),
     ?_assertEqual({[1],[3]}, delete({[1], [2,3]}))].

maps_test_() ->
    [?_assertEqual({[4,3,2], []}, map(fun(X) -> X+1 end,
                   list_to_zlist([1,2,3]))),
     ?_assertEqual(list_to_zlist([1,2,3]), rmap(fun(X) -> X-1 end,
                   {[4,3,2], []}))].