anchor.diff:      %% count
       0 = syn:count().
   
  +single_node_when_mnesia_is_disc_find_by_key(_Config) ->
  +    %% set schema location
  +    application:set_env(mnesia, schema_location, disc),
  +    %% create schema
  +    mnesia:create_schema([node()]),
  +    %% start
  +    ok = syn:start(),
  +    %% start process
  +    Pid = syn_test_suite_helper:start_process(),
  +    %% retrieve
  +    undefined = syn:find_by_key(<<"my proc">>),
  +    %% register
  +    ok = syn:register(<<"my proc">>, Pid),
  +    %% retrieve
  +    Pid = syn:find_by_key(<<"my proc">>),
  +    %% kill process
  +    syn_test_suite_helper:kill_process(Pid),
  +    timer:sleep(100),
  +    %% retrieve
  +    undefined = syn:find_by_key(<<"my proc">>).
  +
   two_nodes_when_mnesia_is_ram_find_by_key(Config) ->
       %% get slave
       SlaveNodeName = proplists:get_value(slave_node_name, Config),
  
positive.code:     %% retrieve
      undefined = syn:find_by_key(<<"my proc">>),
      undefined = rpc:call(SlaveNodeName, syn, find_by_key, [<<"my proc">>]).
  
  two_nodes_when_mnesia_is_disc_find_by_pid(Config) ->
      %% get slave
      SlaveNodeName = proplists:get_value(slave_node_name, Config),
      %% set schema location
      application:set_env(mnesia, schema_location, disc),
      rpc:call(SlaveNodeName, mnesia, schema_location, [disc]),
      %% create schema
      mnesia:create_schema([node(), SlaveNodeName]),
      %% start
      ok = syn:start(),
      ok = rpc:call(SlaveNodeName, syn, start, []),
      timer:sleep(100),
      %% start process
      Pid = syn_test_suite_helper:start_process(),
      %% register
      ok = syn:register(<<"my proc">>, Pid),
      %% retrieve
      <<"my proc">> = syn:find_by_pid(Pid),
      <<"my proc">> = rpc:call(SlaveNodeName, syn, find_by_pid, [Pid]),
      %% kill process
      syn_test_suite_helper:kill_process(Pid),
      timer:sleep(100),
      %% retrieve
      undefined = syn:find_by_pid(Pid),
      undefined = rpc:call(SlaveNodeName, syn, find_by_pid, [Pid]).
  
  two_nodes_when_mnesia_is_ram_process_count(Config) ->
      %% get slave
  
negative.code:             single_node_when_mnesia_is_ram_find_by_pid,
              single_node_when_mnesia_is_ram_re_register_error,
              single_node_when_mnesia_is_ram_unregister,
              single_node_when_mnesia_is_ram_process_count,
              single_node_when_mnesia_is_disc_find_by_key
          ]},
          {two_nodes_process_registration, [shuffle], [
              two_nodes_when_mnesia_is_ram_find_by_key,
              two_nodes_when_mnesia_is_ram_process_count,
              two_nodes_when_mnesia_is_disc_find_by_pid
          ]}
      ].
  %% -------------------------------------------------------------------
  