anchor.diff:  
       % sequential tests
       stale_upload_file_should_be_deleted_test/1,
  -    upload_with_time_warps_test/1
  +    upload_with_backward_time_warps_test/1,
  +    upload_with_forward_time_warps_test/1
   ]).
   
   % Exported for rpc calls
  
positive.code:     force_stale_uploads_removal(krakow),
      ?assertMatch(true, authorize_chunk_upload(krakow, user1, FileGuid)),
  
      time_test_utils:simulate_seconds_passing(2),
      force_stale_uploads_removal(krakow),
      ?assertMatch(false, authorize_chunk_upload(krakow, user1, FileGuid)),
  
      Node = oct_background:get_random_provider_node(krakow),
      UserSessId = oct_background:get_user_session_id(user1, krakow),
      ?assertMatch({error, ?ENOENT}, lfm_proxy:stat(Node, UserSessId, ?FILE_REF(FileGuid)), ?ATTEMPTS).
  
  
  upload_with_time_warps_test(_Config) ->
      [#object{guid = FileGuid}] = onenv_file_test_utils:create_and_sync_file_tree(
          user1, space_krk, #file_spec{}
      ),
  
negative.code: %%%===================================================================
  %%% Internal functions
  %%%===================================================================
  
  
  %% @private
  -spec assert_file_does_not_exist(
      oct_background:entity_selector(),
      oct_background:entity_selector(),
      file_id:file_guid()
  ) ->
      ok.
  assert_file_does_not_exist(ProviderSelector, UserSelector, FileGuid) ->
      Node = oct_background:get_random_provider_node(ProviderSelector),
      UserSessId = oct_background:get_user_session_id(UserSelector, ProviderSelector),
      ?assertMatch({error, ?ENOENT}, lfm_proxy:stat(Node, UserSessId, ?FILE_REF(FileGuid)), ?ATTEMPTS).
  
  
  %% @private
  