Switching Data Sources: Testing Data Equivalence

receipt_data_source_equivalence_spec.rb

RSpec.describe ReceiptDataSourceEquivalence do
  before(:suite) do
    @repository_receipt_data_source ||= Repositories::ReceiptDataSource.new(environment: Rails.env)
    @service_receipt_data_source ||= Services::ReceiptDataSource.new(environment: Rails.env)
    
    @local_records = @repository_receipt_data_source.all.collect(&:id)
    @api_records = @service_receipt_data_source.all.collect(&:id)
    @on_records = Array(@local_records & @api_records)
  end

  describe "receipts list call" do
    it "provides receipts with the same set of ids, each of which have equivalent numbers" do
      expect(Set.new(local_records)).to eq(Set.new(api_records))
    end
  end

  describe "receipts detail call" do
    it "given an id, provides a receipt with the same attributes from local database or API"
      @on_records.each do |id|
        local_record = @repository_receipt_data_source.get(id)
        api_record = @service_receipt_data_source.get(id)

        expect local_record.number.to eq(api_record.number)
      end
    end
  end
end