Question

I am setting up a many to many relationship using the :through method and want to test that I have set everything up correctly.

class MenuItem < ActiveRecord::Base
  belongs_to :products #burger
  belongs_to :additions #extra mustard
end

Products would be something like hamburger

class Product < ActiveRecord::Base
  has_many :menu_items
  has_many :additions, through: :menu_items
end

additions would be something like extra mustard or pickles

class Addition < ActiveRecord::Base
  has_many :menu_items
  has_many :products, through: :menu_items
end

I have set up my fixtures so that a hamburger should have 2 additions associated with it. Now I want to test that the association works. Not exactly sure how to do this. I tried this:

in the fixture I set hamburger to have an id of 22. also set the burger to have mustard and pickles (2 additions).

test "product 22 should have 2 additions associated with it" do 
  menu_item = Product.find(22).additions
  assert_equal menu_item.count, 2 
end

I get an uninitialized constants error

NameError: uninitialized constant Product::Additions

I am sure that I am just misunderstanding something. Would really appreciate any pointers.

Answer 1

The error is because you need to use singular for belongs_to.

class MenuItem < ActiveRecord::Base
  belongs_to :product #burger
  belongs_to :addition #extra mustard
end