Do not autoset Person#contacts_list

app/models/person.rb

@@ -32,12 +32,4 @@ class Person < ApplicationRecord
   ###############
 
   validates :contacts_list, uniqueness: true
-
-  #############
-  # Callbacks #
-  #############
-
-  before_validation do
-    self.contacts_list ||= ContactsList.new
-  end
 end

factories/people.rb

@@ -2,6 +2,8 @@
 
 FactoryBot.define do
   factory :initial_person, class: Person do
+    association :contacts_list
+
     first_name { Faker::Name.first_name }
     middle_name { Faker::Name.first_name }
     last_name { Faker::Name.last_name }