Find or create record through factory_girl association

You can to use initialize_with with find_or_create method

FactoryGirl.define do
  factory :group do
    name "name"
    initialize_with { Group.find_or_create_by_name(name)}
  end

  factory :user do
    association :group
  end
end

It can also be used with id

FactoryGirl.define do
  factory :group do
    id     1
    attr_1 "default"
    attr_2 "default"
    ...
    attr_n "default"
    initialize_with { Group.find_or_create_by_id(id)}
  end

  factory :user do
    association :group
  end
end

For Rails 4

The correct way in Rails 4 is Group.find_or_create_by(name: name), so you’d use

initialize_with { Group.find_or_create_by(name: name) } 

instead.