# Call factory with the factory name and an optional method_name
#
#   factory(:user)
#   factory(:expensive_product, :method_name => :product)
#
# Then in all of your it/specify blocks you can call upon a a super-mocked,
# majorly-stubbed Factory.
#
#   describe "Something awesome"
#     factory(:long_factory_name_for_user_model, :method_name => :user)
#
#     it "should do something" do
#       user(:attribute => 'James').attribute.should == 'James'
#     end
#
#     it "should do more than just that" do
#       u = user({:attribute => 'James'}, {:stub => 'a result'})
#       u.stub should == 'a result'
#     end
#   end

def factory(factory_name, options = {})
  method_name = (options[:method_name] || factory_name).to_s.to_sym

  define_method(method_name) do |*args|
    var_name = "@#{method_name}"
    value = instance_variable_get(var_name)
    return value if value

    attributes = args.shift || {}
    stubs = args.shift || {}

    super_mock = Proc.new { |factory_name, attributes, stubs|
      Factory(factory_name, attributes).tap do |super_mock|
        super_mock.stub!(stubs)
      end
    }

    instance_variable_set(var_name, super_mock.call(factory_name, attributes, stubs))
  end
end