ruby on rails - Validate presence of shipping address unless it's same as billing address -

i have in order class. want validate presence of shipping_address unless it's same billing_address. specs keep failing, however.

class order < activerecord::base   attr_writer :ship_to_billing_address    belongs_to :billing_address,  class_name: 'address'   belongs_to :shipping_address, class_name: 'address'    accepts_nested_attributes_for :billing_address, :shipping_address    validates :shipping_address, presence: true, unless: -> { self.ship_to_billing_address? }    def ship_to_billing_address     @ship_to_billing_address ||= true   end    def ship_to_billing_address?     self.ship_to_billing_address   end end 

but keep getting failed specs (expected example not valid):

describe "shipping_address_id"   context "when shipping address different billing address"     before { @order.ship_to_billing_address = false }     it_behaves_like 'a foreign key', :shipping_address_id   end end  shared_examples 'a foreign key' |key|   "can't nil, blank, or not int"     [nil, "", " ", "a", 1.1].each |value|       @order.send("#{key}=", value)       @order.should_not be_valid     end   end end 

form code:

= f.check_box :ship_to_billing_address | use shipping address billing address. 

your ship_to_billing_address method implementation wrong. sets @ship_to_billing_address true if set false before. more correct implementation:

   def ship_to_billing_address      @ship_to_billing_address = true if @ship_to_billing_address.nil?      @ship_to_billing_address       end 

examples:

irb(main):001:0> class order irb(main):002:1>   attr_writer :stba irb(main):003:1>   def stba irb(main):004:2>     @stba ||= true irb(main):005:2>   end irb(main):006:1> end => nil irb(main):007:0>  irb(main):008:0* o = order.new => #<order:0x8bbc24c> irb(main):009:0> o.stba = false => false irb(main):010:0> o.stba   irb(main):011:0> class order2 irb(main):012:1>   attr_writer :stba irb(main):013:1>   def stba irb(main):014:2>     if @stba.nil? irb(main):015:3>       @stba = true irb(main):016:3>     else irb(main):017:3*       @stba irb(main):018:3>     end irb(main):019:2>   end irb(main):020:1> end => nil irb(main):021:0> o = order2.new => #<order2:0x8b737e0> irb(main):022:0> o.stba = false => false irb(main):023:0> o.stba => false