How to get a list of traits passed to a factory_girl method?

Question

#spec
let(:price) { create :price,:some_trait,:my_trait }

#factory
FactoryGirl.define do
  factory :price, class: 'Prices::Price' do
    ...

    after(:build) do |p,e|

      # How I can get the traits passed to the create method?
      # => [:some_trait,:my_trait]

      if called_traits_does_not_include(:my_trait) # fake code
        build :price_cost,:order_from, price:p
      end
    end

    ...
  end
end

How I can get the traits which are passed to create in the factory's after(:build) callback?

Answer 1

I don't know of a factory_girl feature which explicitly supports this. But I can think of two partial solutions that might work in specific cases:

1. Set a transient attribute in the trait:

   trait :my_trait do
     using_my_trait
   end
   
   factory :price do
     transient do
       using_my_trait false
     end
   
     after :build do |_, evaluator|
       if evaluator.using_my_trait
         # Do stuff
       end
     end
   
   end
   

   This method requires a transient attribute for each trait that you want to track.

2. If you don't need to know what traits were used in an after :build callback but you want to track multiple traits without adding a transient attribute for each one, add the trait to a list in an after :build callback in the trait:

   trait :my_trait do
     after :build do |_, evaluator|
       evaluator.traits << :my_trait
     end
   end
   
   factory :price do
     transient do
       traits []
     end
   
     before :create do |_, evaluator|
       if evaluator.traits.include? :my_trait
         # Do stuff
       end
     end
   
   end
   

   (Callbacks in traits run before the corresponding callbacks in factories, so if you note a trait in its callback the earliest you can see it is in before :create.) This might be better than the first method if you wanted to track traits in a lot of factories, which would make adding a transient attribute for each trait more painful.