anchor.diff:              true;
           {error, ?ENOENT} ->
               false
  +    end.
  +
  +create_file(Config, Path) ->
  +    [Worker | _] = ?config(op_worker_nodes, Config),
  +    SessionId = ?config({session_id, 1}, Config),
  +
  +    case lfm_proxy:create(Worker, SessionId, {path, utils:ensure_unicode_binary(Path)}, ?FILE_PERMISSIONS) of
  +        {ok, UUID} -> UUID;
  +        {error, Code} -> {error, Code}
  +    end.
  +
  +%% FileKey type is file_id_or_path() :: {uuid, file_uuid()} | { path, file_path()}
  +open_file(Config, FileKey, OpenMode) ->
  +    [Worker | _] = ?config(op_worker_nodes, Config),
  +    SessionId = ?config({session_id, 1}, Config),
  +
  +    case lfm_proxy:open(Worker, SessionId, FileKey, OpenMode) of
  +        {error, Error} -> {error, Error};
  +        FileHandle -> FileHandle
  +    end.
  +
  +write_to_file(Config, Path, Data) ->
  +    %%TODO maybe Offset sholud be function argument ?
  +    [Worker | _] = ?config(op_worker_nodes, Config),
  +
  +    FileHandle = open_file(Config, {path, Path}, write),
  +    case lfm_proxy:write(Worker, FileHandle, ?OFFSET, Data) of
  +        {error, Error} -> {error, Error};
  +        Result -> Result
  +    end.
  +
  +get_file_content(Config, Path, Size) ->
  +    %%TODO maybe Offset sholud be function argument ?
  +    [Worker | _] = ?config(op_worker_nodes, Config),
  +
  +    FileHandle = open_file(Config, {path, Path}, write),
  +    case lfm_proxy:read(Worker, FileHandle, ?OFFSET, Size) of
  +        {error, Error} -> {error, Error};
  +        Result -> Result
       end.
positive.code: -export([all/0, init_per_suite/1, end_per_suite/1, init_per_testcase/2,
      end_per_testcase/2]).
  
  -export([choose_adequate_handler/1, use_supported_cdmi_version/1,
      use_unsupported_cdmi_version/1, create_dir_test/1]).
  
  -performance({test_cases, []}).
  all() -> [choose_adequate_handler, use_supported_cdmi_version,
      use_unsupported_cdmi_version, create_dir_test].
  
  -define(MACAROON, "macaroon").
  
negative.code: -include_lib("ctool/include/logging.hrl").
  -include_lib("ctool/include/test/test_utils.hrl").
  -include_lib("ctool/include/test/assertions.hrl").
  -include_lib("ctool/include/posix/file_attr.hrl").
  -include_lib("ctool/include/posix/errors.hrl").
  -include_lib("annotations/include/annotations.hrl").
  
  