anchor.diff:  %%% TESTS %%%
   %%%%%%%%%%%%%
   
  -lookup_by_channel(Config) ->
  +by_channel(Config) ->
       Chan = ?config(chan, Config),
       Tokens = [ logplex_token:new(Chan, list_to_binary(Name))
                  || Name <- ["heroku", "app", "postgres", "bob"]],
  
positive.code:     Config.
  
  %% Runs before the test case. Runs in the same process.
  init_per_testcase(lookup_by_channel, Config) ->
      logplex_db:start_link(),
      [{chan, 1} | Config];
  init_per_testcase(_CaseName, Config) ->
  
negative.code:     [ logplex_token:cache(Token)
        || Token <- Tokens ],
      true = lists:sort(Tokens) =:=
          lists:sort(logplex_token:lookup_by_channel(Chan)),
      logplex_token:delete_by_channel(Chan),
      [] = logplex_token:lookup_by_channel(Chan).
  