Remove unused app config options

app/helpers/spree/base_helper.rb

@@ -3,7 +3,7 @@
 module Spree
   module BaseHelper
     def available_countries
-      checkout_zone = Zone.find_by(name: Spree::Config[:checkout_zone])
+      checkout_zone = Zone.find_by(name: ENV.fetch("CHECKOUT_ZONE", nil))
 
       countries = if checkout_zone && checkout_zone.kind == 'country'
                     checkout_zone.countries

config/application.rb

@@ -93,7 +93,6 @@ class Application < Rails::Application
     #       of Spree
     initializer 'ofn.spree_locale_settings', before: 'spree.promo.environment' do |app|
       Rails.application.reloader.to_prepare do
-        Spree::Config['checkout_zone'] = ENV['CHECKOUT_ZONE']
         Spree::Config['currency'] = ENV['CURRENCY']
       end
     end

spec/base_spec_helper.rb

@@ -235,14 +235,12 @@
   end
 
   default_country_id = DefaultCountry.id
-  checkout_zone = Spree::Config[:checkout_zone]
   currency = Spree::Config[:currency]
   # Ensure we start with consistent config settings
   config.before(:each) do
     reset_spree_preferences do |spree_config|
       # These are all settings that differ from Spree's defaults
       spree_config.default_country_id = default_country_id
-      spree_config.checkout_zone = checkout_zone
       spree_config.currency = currency
       spree_config.shipping_instructions = true
     end

spec/helpers/spree/base_helper_spec.rb

@@ -10,11 +10,12 @@
 
     before do
       3.times { create(:country) }
+      allow(ENV).to receive(:fetch).and_call_original
     end
 
     context "with no checkout zone defined" do
       before do
-        Spree::Config[:checkout_zone] = nil
+        allow(ENV).to receive(:fetch).and_return(nil)
       end
 
       it "return complete list of countries" do
@@ -27,7 +28,7 @@
         before do
           @country_zone = create(:zone, name: "CountryZone")
           @country_zone.members.create(zoneable: country)
-          Spree::Config[:checkout_zone] = @country_zone.name
+          allow(ENV).to receive(:fetch).and_return(@country_zone.name)
         end
 
         it "return only the countries defined by the checkout zone" do
@@ -40,7 +41,7 @@
           state_zone = create(:zone, name: "StateZone")
           state = create(:state, country:)
           state_zone.members.create(zoneable: state)
-          Spree::Config[:checkout_zone] = state_zone.name
+          allow(ENV).to receive(:fetch).and_return(state_zone.name)
         end
 
         it "return complete list of countries" do