anchor.diff:  abs_environment_closure_negative_test_() ->
     {foreachx,
      fun(Options) ->
  -       case proplists:get_bool(mock_tpar, Options) of
  -         true  -> mock_tpar();
  -         false -> nothing
  -       end,
  +       mock_if_needed(Options),
          setup()
      end,
      fun(Options, Pid) ->
          cleanup(Pid),
  -       case proplists:get_bool(mock_tpar, Options) of
  -         true  -> unmock_tpar();
  -         false -> nothing
  -       end
  +       unmock_if_needed(Options)
      end,
      lists:append(
        [
  
positive.code: b_abs_returned_by_various_expressions(UndefVarIdA) ->
    BAbs = {b_abs, [], [s("x")], s(UndefVarIdA)}, %% \_ x -> A
    [
     {primop, fun(X) -> X end, [BAbs]},
     %%
     {'@', s("#.t"), {t, [{{dim,"t"}, BAbs}]}},
     %% "#.t @ [t <- \_x -> A]"
  
negative.code:   ].
  
  
  %% Internals - Mocking
  
  compose_tree_and_b_abs(ASTGenFun, {Options, FAbs}) when is_list(Options) ->
    {Options, ASTGenFun(FAbs)};
  