Rails, FactoryGirl, and has_and_belongs_to_many

gistfile1.txt

When testing has_and_belongs_to_many models using rspec and factory girl you should setup your factory the following way:

FactoryGirl.define do
  factory :foo do
    name "Foo" 
  end

  factory :bar do
    name "Bar"
    foos { |a| [a.association(:foo)] }
  end
end

credit: https://coderwall.com/p/o5yssw