Url normalization. Appends http to url which doesn't have it

application_helper.rb

module ApplicationHelper
  def expand_url(url)
    return url if url.blank? || /(http:\/\/|https:\/\/)/ =~ url
    "http://#{url}"
  end
end

application_helper_spec.rb

require 'rails_helper'

RSpec.describe ApplicationHelper do
  RSpec.describe '#expand_url' do
    it { expect(helper.expand_url('google.com')).to eq('http://google.com') }
    it { expect(helper.expand_url('http://google.com')).to eq('http://google.com') }
    it { expect(helper.expand_url('https://google.com')).to eq('https://google.com') }
    it { expect(helper.expand_url('')).to eq('') }
  end
end