Create FactoryBot User with has_one relationship - ruby-on-rails

Question

Background:
I am trying to create a FactoryBot object which is related with has_one/belongs_to
User has_one Car
Car has_one Style
Style has an attribute {style_number:"1234"}
Question
My controller references user, user has_one Car, Car has_one Style, and I need to set these values within FactoryBot.
How do I create a User, who also has a Car object, that has a Style object?
I read the documentation https://github.com/thoughtbot/factory_bot/blob/master/GETTING_STARTED.md
However, I am not understanding how they recommend doing this. Figured out, I need to nest the three objects, but confused on the syntax.
Controller
before_action :authenticate_user!
before_action :set_steps
before_action :setup_wizard
include Wicked::Wizard
def show
#user = current_user
#form_object = form_object_model_for_step(step).new(#user)
render_wizard
end
private
def set_steps
if style_is_1234
self.steps = car_steps.insert(1, :style_car)
else
self.steps = car_steps
end
end
def style_is_1234
if params.dig(:form_object, :style_number)
(params.dig(:form_object, :style_number) & ["1234"]).present?
else
(current_user.try(:car).try(:style).try(:style_number) & ["1234"]).present?
end
end
def car_steps
[:type,:wheel, :brand]
end
Rspec Test
Factory :User
FactoryBot.define do
factory :user, class: User do
first_name { "John" }
last_name { "Doe" }
email { Faker::Internet.email }
password { "somepassword" }
password_confirmation { "some password"}
end
end
Before method
before(:each) do
#request.env["devise.mapping"] = Devise.mappings[:user]
user = FactoryBot.create(:user)
sign_in user
Test
User needs to be signed in and User.car.style.style_number needs to be set to "1234"
context "Requesting with second step CarStyle" do
it "should return success" do
get :show, params: { :id => 'car_style' }
expect(response.status).to eq 200
end
end
Currently this test fails because User.Car.Style.style_number is not set to "1234".
Trial 1 (https://github.com/thoughtbot/factory_bot_rails/issues/232)
FactoryBot.define do
factory :user, class: User do
first_name { "John" }
last_name { "Doe" }
email { Faker::Internet.email }
password { "somepassword" }
password_confirmation { "some password"}
car
end
end
FactoryBot.define do
factory :car, class: Car do
make { "Holden" }
model { "UTE" }
end
end
FactoryBot.define do
factory :style, class: Style do
color { "blue" }
for_car
trait :for_car do
association(:styable, factory: :car)
end
end
end
Error from trail 1
SystemStackError:
stack level too deep
Trail 2
I tried srng's recommendation
EDIT: For a polymorphic association try;
FactoryBot.define do
factory :car, class: Car do
make { "Holden" }
model { "UTE" }
association :stylable, factory: :style
end
end
and got error:
ActiveRecord::RecordInvalid: Validation failed: Stylable must exist
I think this is a rails 5 issue. https://github.com/rails/rails/issues/24518
However, I would like to keep my code with the adding the optional:true. Any way to do this?
Trail 3
FactoryBot.define do
factory :car, class: Car do
make { "Holden" }
model { "UTE" }
after(:create) do |car|
create(:style, stylable: car)
end
end
end
Tried Srng's second recommendation and although it worked for him, I got a slightly different error:
ActiveRecord::RecordInvalid:
Validation failed: User must exist

Answer 1

In order to create dependent Factories you have to create a factory for each model, and then just add the dependent Model name to your factory, ie.
FactoryBot.define do
factory :user, class: User do
first_name { "John" }
last_name { "Doe" }
email { Faker::Internet.email }
password { "somepassword" }
password_confirmation { "some password"}
car
end
end
FactoryBot.define do
factory :car, class: Car do
make { "Holden" }
model { "UTE" }
style
end
end
FactoryBot.define do
factory :style, class: Style do
color { "blue" }
end
end
EDIT:
Relevant code;
# Factories
FactoryBot.define do
factory :user, class: User do
first_name { "John" }
last_name { "Doe" }
email { Faker::Internet.email }
password { "somepassword" }
password_confirmation { "some password"}
after(:create) do |user|
user.car ||= create(:car, :user => user)
end
end
end
factory :style, class: Style do
style_number { "Blue" }
end
factory :car, class: Car do
name { "Holden" }
trait :style do
association :stylable, factory: :style
end
end
#models
class Car < ApplicationRecord
has_one :style, as: :styleable
end
class Style < ApplicationRecord
belongs_to :styleable, polymorphic: true
belongs_to :car
end
# Migrations - The belongs_to is the only important one
class CreateStyles < ActiveRecord::Migration[5.2]
def change
create_table :styles do |t|
t.string :style_number
t.belongs_to :stylable, polymorphic: true
t.timestamps
end
end
end
class CreateCars < ActiveRecord::Migration[5.2]
def change
create_table :cars do |t|
t.string :name
t.timestamps
end
end
end

Answer 2

There can be an another way of attaining this using a transient block in the Factory.
Hope the below snippet may help you to explore in new way.
Note: This is not tested.
## To Create a user in test case
# create(:user) # defaults to 1234 style number
# create(:user, car_style_number: 5678)
DEFAULT_STYLE_NUMBER = 1234
FactoryBot.define do
factory :user do
transient do
car_style_number { DEFAULT_STYLE_NUMBER }
end
first_name { "John" }
last_name { "Doe" }
email { Faker::Internet.email }
after(:create) do |user, evaluator|
user.car = create(:car, car_style_number: evaluator.car_style_number, user: user)
end
end
end
FactoryBot.define do
factory :car do
transient do
car_style_number { DEFAULT_STYLE_NUMBER }
end
make { "Holden" }
model { "UTE" }
after(:create) do |car, evaluator|
car.style = create(:style, style_number: evaluator.car_style_number, car: car)
end
end
end
FactoryBot.define do
factory :style do
style_number { DEFAULT_STYLE_NUMBER }
end
end