Add configuration option: recalculate_complete_orders

This gem allows recalculating complete orders until they are shipped,
because Solidus allows changing an order's contents until the order is
shipped.

This change adds a configuration option that disables the
recalculation of orders after they are completed. Some shops make
changes to existing promotions, and expect that this does not change
complete, but unshipped orders.

app/models/solidus_friendly_promotions/friendly_promotion_adjuster.rb

@@ -13,7 +13,8 @@ def initialize(order, dry_run_promotion: nil)
     def call
       order.reset_current_discounts
 
-      return order if order.shipped?
+      return order if (!SolidusFriendlyPromotions.config.recalculate_complete_orders && order.complete?) || order.shipped?
+
       discounted_order = DiscountOrder.new(order, promotions, dry_run: dry_run).call
 
       PersistDiscountedOrder.new(discounted_order).call unless dry_run

lib/solidus_friendly_promotions/configuration.rb

@@ -5,10 +5,12 @@
 module SolidusFriendlyPromotions
   class Configuration < Spree::Preferences::Configuration
     attr_accessor :sync_order_promotions
+    attr_accessor :recalculate_complete_orders
     attr_accessor :promotion_calculators
 
     def initialize
       @sync_order_promotions = true
+      @recalculate_complete_orders = true
       @promotion_calculators = NestedClassSet.new
     end
 

spec/lib/solidus_friendly_promotions/configuration_spec.rb

@@ -54,4 +54,16 @@
       config.sync_order_promotions = true
     end
   end
+
+  describe ".recalculate_complete_orders" do
+    subject { config.recalculate_complete_orders }
+
+    it { is_expected.to be true }
+
+    it "can be set to false" do
+      config.recalculate_complete_orders = false
+      expect(subject).to be false
+      config.recalculate_complete_orders = true
+    end
+  end
 end

spec/models/solidus_friendly_promotions/friendly_promotion_adjuster_spec.rb

@@ -33,6 +33,33 @@
           subject
           expect(adjustable.current_discounts).to be_empty
         end
+
+        context "if order is complete but not shipped" do
+          let(:line_item) { order.line_items.first }
+          let(:order) { create(:order_ready_to_ship) }
+
+          it "creates the adjustment" do
+            expect {
+              subject
+              order.save
+            }.to change { adjustable.reload.adjustments.length }.by(1)
+          end
+
+          context "but the preference to recalculate complete orders is set to false" do
+            around do |example|
+              SolidusFriendlyPromotions.config.recalculate_complete_orders = false
+              example.run
+              SolidusFriendlyPromotions.config.recalculate_complete_orders = true
+            end
+
+            it "will not create the adjustment" do
+              expect {
+                subject
+                order.save
+              }.not_to change { adjustable.reload.adjustments.length }
+            end
+          end
+        end
       end
 
       context "with a calculator that returns zero" do