describe Support::Helpers::UPC do
  let(:instance) { described_class.new }
  describe "#generate" do
    it "assigns a 12-digit number to @result" do
      instance.generate
      expect(instance.result.size).to eql 12
    end

    it "generates 036000241457 correctly" do
      allow(instance).to receive(:random_11_digit_number) { "03600024145" }
      instance.generate
      expect(instance.result[11]).to eql "7"
    end
  end
end