its.rb

module Sinefunc
  module SpecHelpers
    module Sugar
      def its(attribute, &block)
        describe(attribute) do
          define_method(:subject) { super().send(attribute) }
            it(&block)
          end
        end
      end
    end
  end
end

Rspec.configure { |c| c.extend Sinefunc::SpecHelpers::Sugar }