sequence(:example_id, & &1) put chars instead of integer about ex_machina HOT 3 CLOSED

iex(1)> a = [65, 66, 67]
'ABC'
iex(2)> hd(a)
65

# test/support/data_case.ex
allowed_ids = [id_1 | _] = [next_id(), next_id(), next_id(), next_id()]

# test/support/factory.ex
use ExMachina.Ecto
def next_id, do: sequence(:id, & &1)

# run mix test.watch with dbg(allowed_ids) been added
#test A
    subject_info: %Context.SubjectInfo{                                                                                           
      user_token: "admin token",                                                                                                                            
      user_id: 389,                                                                                                                                         
      allowed_ids: 'STUV',                                                                                                                                     
      __unknown_fields__: [] 

#test B
    subject_info: %Context.SubjectInfo{
      user_token: "admin token",
      user_id: 1000,
      allowed_ids: '{|}~',
      __unknown_fields__: []
    },

#test C
    subject_info: %Context.SubjectInfo{                                                                                           
      user_token: "admin token",                                                                                                                            
      user_id: 802,                                                                                                                                         
      allowed_ids: '\a\b\t\n',                                                                                                                                 
      __unknown_fields__: []                                                                                                                                
    },                                                                                                                                  

#test D
    subject_info: %Context.SubjectInfo{
      user_token: "admin token",
      user_id: 31,
      allowed_ids: [0, 1, 2, 3],
      __unknown_fields__: []
    },