FactoryBot one record associated with many attributes - ruby-on-rails

Question

I have User, Assignment and Department models.
My Assignment model has 2 belongs_to associations with the User model as requestor and assignee.
The User and Assignment model also in turn belongs_to a department.
I want to run a validation on my Assignment such that the assignment, requestor and assignee all belong to the same department.
This is my code for the models
# app/models/assignment.rb
class Assignment < ApplicationRecord
belongs_to :requestor, class_name: "User", foreign_key: "requested_by"
belongs_to :assignee, class_name: "User", foreign_key: "assigned_to"
belongs_to :department
end
# app/models/user.rb
class User < ApplicationRecord
has_many :user_departments, class_name: "UserDepartment"
has_many :departments, through: :user_departments
belongs_to :department
end
# app/models/department.rb
class Department < ApplicationRecord
has_many :user_departments, class_name: "UserDepartment"
has_many :users, through: :user_departments
has_many :assignments
has_many :users
end
This is the code for my test
# spec/factories/assignment.rb
FactoryBot.define do
sequence(:title) { |n| "Title #{n}" }
sequence(:description) { |n| "Description #{n}" }
factory :assignment do
title
description
image { Rack::Test::UploadedFile.new(Rails.root.join('spec/support/Floyd.jpeg'), 'image/jpeg') }
release_date { DateTime.now >> 1 }
department { create(:department) }
requestor create(:user, :bm, department: "I want to use the same department as created in earlier line here")
assignee create(:user, :mu, department: "I want to use the same department as created in earlier line here")
end
end
Where should I define the department so I can use the same department across all three associations.

Answer 1

Have you tried self.department? It worked in my code:
# spec/factories/assignment.rb
FactoryBot.define do
sequence(:title) { |n| "Title #{n}" }
sequence(:description) { |n| "Description #{n}" }
factory :assignment do
title
description
image { Rack::Test::UploadedFile.new(Rails.root.join('spec/support/Floyd.jpeg'), 'image/jpeg') }
release_date { DateTime.now >> 1 }
department { create(:department) }
requestor { create(:user, :bm, department: self.department) }
assignee { create(:user, :mu, department: self.department) }
end
end

Answer 2

Hope I got the question right. You want the same department on all the models.
This is a thing you actually do in the spec.
describe Foo::Bar do
before(:each) do
#department = create(:deparment)
#assignment = create(:assignment, department: #department)
#user = create(:user, department: department)
# ....
end
But this always depends on how your overall structure is. When the assignment is the center model and always has a department you could do something like
describe Foo::Bar do
before(:each) do
#assignment = create(:assignment)
#user = create(:user, department: #assignment.department)
# ....
end