ruby on rails - Testing has_many association with RSpec -

i'm trying test hour model rspec, namely class method 'find_days_with_no_hours' behaves scope. business has_many hours associated through sti. find_days_with_no_hours needs called through business object , can't figure out how set in rspec test. want able test like:

bh = @business.hours.find_days_with_no_hours bh.length.should == 2 

i've tried various approaches, creating business object (with, say, business.create), setting @business.hours << mock_model(businesshour, ..., ..., ...) doesn't work.

how done?

class business < activerecord::base    has_many :hours, :as => :hourable  end  class hour < activerecord::base    belongs_to :hourable, :polymorphic => true    def self.find_days_with_no_hours     where("start_time null")   end  end 

you can't test arel method creating object via mocks. arel going go straight database, , not see mocks or you've created in memory. grab factory_girl , define hour factory yourself:

factory.define :hour |f|   f.start_time {time.now} end  factory.define :unstarted_day, :parent => :hour |f|   f.start_time nil end 

and in test...

business = factory.create(:business) business.hours << factory.create(:unstarted_day)  bh = business.hours.find_days_with_no_hours bh.length.should == 1 

however, factory_girl personal preference setting known state, can use create statements or fixtures, problem trying use mock_model() (which prevents database hit), , using method queries database.