anchor.diff:      ?line true = T0 == ets:all(),
       ok.
   
  +digraph_fail(ExitReason, Fail) ->
  +    {'EXIT', {ExitReason, [{sofs,family_to_digraph,A,_}|_]}} = Fail,
  +    case {test_server:is_native(sofs),A} of
  +	{false,[_,_]} -> ok;
  +	{true,2} -> ok
  +    end.
  +
   constant_function(suite) -> [];
   constant_function(doc) -> [""];
   constant_function(Conf) when is_list(Conf) ->
  
positive.code: 
      ?line {'EXIT', {badarg, _}} = 
          (catch family_to_digraph(set([a]))),
      ?line {'EXIT', {badarg, [{sofs,family_to_digraph,[_,_],_}|_]}} =
          (catch family_to_digraph(set([a]), [foo])),
      ?line {'EXIT', {badarg, [{sofs,family_to_digraph,[_,_],_}|_]}} =
          (catch family_to_digraph(F, [foo])),
      ?line {'EXIT', {cyclic, [{sofs,family_to_digraph,[_,_],_}|_]}} =
          (catch family_to_digraph(family([{a,[a]}]),[acyclic])),
  
      ?line G1 = family_to_digraph(E),
      ?line {'EXIT', {badarg, _}} = (catch digraph_to_family(G1, foo)),
  
negative.code:                difference(S, RR)),
  
      %% The function external:foo/1 is undefined.
      case test_server:is_native(sofs) of
  	true ->
  	    %% Create an export entry for external:foo/1 to work
  	    %% around a bug in the native code. If there is no
  	    %% export entry, the exception will be
  	    %% {badfun,{external,foo}}. Remove in R16 when tuple
  	    %% funs are removed.
  	    (catch external:foo([]));
  	false ->
  	    ok
      end,
      ?line {'EXIT', {undef, _}} =    
   	(catch projection({external,foo}, set([a,b,c]))),
      ok.
  