anchor.diff:    fold_by_id/1,
     change_since/1,
     revdiff/1,
  -  get_revisions/1
  +  get_revisions/1,
  +  put_rev/1
   ]).
   
   all() ->
  
positive.code:   {ok, Doc4} = barrel_db:get(<<"testdb">>, DocId, [{history, true}]),
    Revisions = barrel_doc:parse_revisions(Doc4),
    Revisions == [RevId2, RevId].
  
  fold_by_id(_Config) ->
    Doc = #{ <<"_id">> => <<"a">>, <<"v">> => 1},
  
negative.code:     get_revisions,
      fold_by_id,
      change_since,
      revdiff,
      put_rev
    ].
  
  init_per_suite(Config) ->
  