anchor.diff:  -module(dk_q).
  +-ifdef(TEST).
   -include_lib("proper/include/proper.hrl").
  +-include_lib("eunit/include/eunit.hrl").
  +-endif.
   
   %% API
   -export([execute/1]).
  
positive.code: nested_or(_) ->
      false.
  
  %% Local variables:
  %% mode: erlang
  %% fill-column: 78
  
negative.code:     Q#term_q.keyword.
  
  %%----------------------------------------------------------------------------
  %% Tests
  %%----------------------------------------------------------------------------
  
  -ifdef(TEST).
  
  proper_test_() ->
      [{atom_to_list(F),
        fun () -> ?assert(proper:quickcheck(?MODULE:F(), [long_result])) end}
       || {F, 0} <- ?MODULE:module_info(exports), F > 'prop_', F < 'prop`'].
  
  prop_all_not_element() ->
      ?FORALL(X, q(), not_element(dnf({X,depth(X)}))).
  