NDC ID Formatter

medication_reconciliation_creator.rb

# revise the MedicationReconciliationCreator class
# to use the newly introduced NdcIdFormatter

class MedicationReconciliationCreator

# existing code to build a reconciled medication

  def formatted_ndc_id(ndc_id)
    NdcIdFormatter.format(ndc_id)
  end
end

# For test coverage for this class, I would
# only test the happy path and not stub out
# the call to the NdcIdFormatter.

ndc_id_formatter.rb

class NdcIdFormatter
  def self.format(ndc_id)
    new(ndc_id).format
  end

  def initialize(ndc_id)
    @ndc_id = ndc_id
  end

  def format
    # ... code that adds necessary padding ...
  end

  private
  att_reader :ndc_id
end

ndc_id_formatter_spec.rb

RSpec.describe NdcIdFormatter do
  describe ".format" do
    it "removes all hyphens" do
    end

    it "returns nil for empty values" do
      expect(NdcIdFormatter.format("").to be nil
       expect(NdcIdFormatter.format(nil).to be nil
    end

    context "given an ID in the 4-4-2 format" do
      it "adds a leading zero to first section" do
        ndc_id = "0777-3105-02"
        
        NdcIdFormatter.format(ndc_id).to eq("00777310502")
      end
    end

    context "given an ID in the 5-3-2 format" do
      it "adds a leading zero to the middle section" do
      end
    end

    context "given an ID in the 5-4-1 format" do
      it "adds a leading zero to the last section" do
      end
    end
  end
end