Cannot see what I have done wrong

In the Agile Rails tutorial I am revisiting building a cart. I have
followed the steps given in the book to create the class ‘Cart’
thus:

class Cart

attr_reader :items
attr_reader :total_price

def add_product(product)
@items << LineItem.for_product(product)
@total_price += product.price
end

def initialize
@items = []
@total_price = 0.0
end

end
~
“app/models/cart.rb”

I have wired together the other bits in
app/controllers/store_controller.rb and app/models/line_item.rb

class StoreController < ApplicationController

def add_to_cart
product = Product.find(params[:id])
@cart = find_cart
@cart.add_product(product)
redirect_to(:action => ‘display_cart’)
end

def display_cart
@cart = find_cart
@items = @cart.items
end

def index
@products = Product.salable_items
end

private

def find_cart
session[:cart] ||= Cart.new
end

end
~
“app/controllers/store_controller.rb”


class LineItem < ActiveRecord::Base

belongs_to :product

def self.for_product(product)
item = self.new
item.quantity = 1
item.product = product
item.unit_price = product.price
item
end
end
~
“app/models/line_item.rb”


When I attempt to add an item from store/index.rhtml I get this:

NoMethodError in Store#add_to_cart

undefined method `add_product’ for #<Cart:0xb7838a68
@total_price=0.0, @items=[]>

RAILS_ROOT: script/…/config/…

I have successfully completed this part of the tutorial at least
three times now and I cannot for the life of me see what I have
done differently this time. Can another pair of eyes see what I
cannot?

Regards,
Jim


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One thing which may help is:

To make also make sure that in LineItem you have:
belongs_to :product

Oops!!!

I meant:

belongs_to :cart

Dominique P. wrote:

One thing which may help is:

To make also make sure that in LineItem you have:
belongs_to :product