-module(maps_map_size).
-export([test/0]).

test() ->
    0 = map_size(id(#{})),
    1 = map_size(id(#{a=>1})),
    1 = map_size(id(#{a=>"wat"})),
    2 = map_size(id(#{a=>1, b=>2})),
    3 = map_size(id(#{a=>1, b=>2, b=>"3","33"=><<"n">>})),

    true = map_is_size(#{a=>1}, 1),
    true = map_is_size(#{a=>1, a=>2}, 1),
    M = #{ "a" => 1, "b" => 2},
    true  = map_is_size(M, 2),
    false = map_is_size(M, 3),
    true  = map_is_size(M#{ "a" => 2}, 2),
    false = map_is_size(M#{ "c" => 2}, 2),

    %% Error cases.
    {'EXIT',{{badmap,[]},_}} = (catch map_size([])),
    {'EXIT',{{badmap,<<1,2,3>>},_}} = (catch map_size(<<1,2,3>>)),
    {'EXIT',{{badmap,1},_}} = (catch map_size(1)),
    ok.

map_is_size(M,N) when map_size(M) =:= N -> true;
map_is_size(_,_) -> false.

%% Use this function to avoid compile-time evaluation of an expression.
id(I) -> I.