Optimize base16 encoding

app/services/irs_attempts_api/envelope_encryptor.rb

@@ -1,3 +1,5 @@
+require 'base16'
+
 module IrsAttemptsApi
   class EnvelopeEncryptor
     Result = Struct.new(:filename, :iv, :encrypted_key, :encrypted_data, keyword_init: true)

config/application.rb

@@ -13,7 +13,6 @@
 require_relative '../lib/fingerprinter'
 require_relative '../lib/identity_job_log_subscriber'
 require_relative '../lib/email_delivery_observer'
-require_relative '../lib/base_16' # Should I need to do this?
 
 Bundler.require(*Rails.groups)
 

lib/base16.rb

@@ -0,0 +1,10 @@
+# See https://www.rfc-editor.org/rfc/rfc4648#section-8
+class Base16
+  def self.encode16(str)
+    str.unpack('H*').first.tap(&:upcase!)
+  end
+
+  def self.decode16(str)
+    [str].pack('H*')
+  end
+end

lib/tasks/attempts.rake

@@ -1,3 +1,5 @@
+require 'base16'
+
 namespace :attempts do
   desc 'Retrieve events via the API'
   task fetch_events: :environment do

spec/lib/base16_spec.rb

@@ -1,4 +1,5 @@
 require 'rails_helper'
+require 'base16'
 
 RSpec.describe Base16 do
 
@@ -34,12 +35,12 @@
     end
   end
 
-  context 'with a less reasonable input', skip: true do
+  context 'with a less reasonable input' do
     context 'given a zany-face emoji' do
       let(:input) { "🤪" }
-      it 'should return the same thing but does not' do
+      it 'returns the same bytes' do
         encoded = described_class.encode16(input)
-        decoded = described_class.decode16(encoded)
+        decoded = described_class.decode16(encoded).force_encoding('UTF-8')
         expect(decoded).to eq input
       end
     end