FactoryGirl association model trouble: “SystemStackError: stack level too deep”

Question

I am using Ruby on Rails 3.0.9, RSpec-rails 2 and FactoryGirl. I am trying to state a Factory association model but I am in trouble.

I have a factories/user.rb

Answer 1

Spyle's excellent answer (still working with Rails 5.2 and RSpec 3.8) will work for most associations. I had a use case where a factory needed to use 2 different factories (or different traits) for a single has_many association (ie. for a scope type method).

What I ended up coming up with was:

# To build user with posts of category == 'Special' and category == 'Regular'
after(:create) do |user, evaluator|
  array = []
  array.push(FactoryBot.create_list(:post, 1, category: 'Regular')
  array.push(FactoryBot.create_list(:post, 1, category: 'Special')
  user.posts = array.flatten
end

This allowed the user to have 1 post of category 'Regular' and 1 post of category 'Special.'