anchor.diff:  -include_lib("eunit/include/eunit.hrl").
   
   -define(DATAFRAME, 'pandas.core.frame.DataFrame').
  +-define(SERIES, 'pandas.core.frame.Series').
   
   -export([all/0, init_per_testcase/2, end_per_testcase/2]).
   -export([test_jun_pandas_columns/1,
  
positive.code:     test_jun_pandas_len_index/1,
      test_jun_pandas_memory_usage/1,
      test_jun_pandas_info_columns/1,
      test_jun_pandas_selection/1]).
  
  all() ->
      [test_jun_pandas_columns,
  
negative.code:      test_jun_pandas_len_index,
       test_jun_pandas_memory_usage,
       test_jun_pandas_info_columns,
       test_jun_pandas_selection,
       test_jun_pandas_single_selection].
  
  init_per_testcase(_, _Config) ->
      % for each case start a new worker
  