leveraging Subject in RSpec - 3

address_spec.rb

describe Address do
  describe "#validations" do
    before(:all) do
      @a = Address.new
      @a.should_not be_valid
    end

    %w(:city :state :country).each do |attr|
      it "must have a #{attr}" do 
        @a.errors_on(attr).should_not be_nil
      end
    end
  end
end