anchor.diff:    put_cat(),
     put_dog(),
   
  -  {200, R1} = test_lib:req(get, "/dbs/testdb/docs/_changes"),
  +  {200, R1} = req_changes("/dbs/testdb/docs/_changes"),
     A1 = jsx:decode(R1, [return_maps]),
     2 = maps:get(<<"last_seq">>, A1),
     Results1 = maps:get(<<"results">>, A1),
     2 = length(Results1),
   
  -  {200, R2} = test_lib:req(get, "/dbs/testdb/docs/_changes?since=1"),
  +  {200, R2} = req_changes("/dbs/testdb/docs/_changes?since=1"),
     A2 = jsx:decode(R2, [return_maps]),
     2 = maps:get(<<"last_seq">>, A2),
     Results2 = maps:get(<<"results">>, A2),
  
positive.code:     <<"changes">> := CatHistory} = hd(Results1),
    [DeleteRevId, CreateRevId] = [binary_to_list(R) || R <- CatHistory],
  
    {200, R2} = test_lib:req(get, "/dbs/testdb/docs/_changes?since=1"),
    A2 = jsx:decode(R2, [return_maps]),
    3 = maps:get(<<"last_seq">>, A2),
    Results2 = maps:get(<<"results">>, A2),
  
negative.code:   put_dog(),
    DeleteRevId = delete_cat(CreateRevId),
  
    {200, R1} = req_changes("/dbs/testdb/docs/_changes?history=all"),
    A1 = jsx:decode(R1, [return_maps]),
    3 = maps:get(<<"last_seq">>, A1),
    Results1 = maps:get(<<"results">>, A1),
  