simple set key

client.rb

class Client < ActiveRecord::Base
  
  after_initialize :set_key

private
  def set_key 
    self.client_key ||= SecureRandom.urlsafe_base64(20, false) 
  end
end

client_spec.rb

require 'spec_helper'

describe Client do
  
  describe "client_key" do
    subject { client.client_key }
    
    context "for a new client" do
      let(:client) { Client.new }
      it "gets a new client key" do
        expect(subject).to_not be_nil
      end
    end
    
    context "for a client loaded from the db"
      let(:saved_client) { c = Client.new; c.save; c }
    
      let(:client) do
        Client.find(saved_client.id)
      end
      
      it "should return the existing client_id" do
        expect(subject).to eq(saved_client.client_key)  
      end
    end
      
  end
  
end