Move adjustments logic from decorator into model

app/models/spree/payment.rb

@@ -15,6 +15,8 @@ module Spree
       class_name: "Spree::Payment", foreign_key: :source_id
     has_many :log_entries, as: :source
 
+    has_one :adjustment, as: :source, dependent: :destroy
+
     before_validation :validate_source
     before_save :set_unique_identifier
 
@@ -125,8 +127,38 @@ module Spree
       res || payment_method
     end
 
+    def ensure_correct_adjustment
+      revoke_adjustment_eligibility if ['failed', 'invalid'].include?(state)
+      return if adjustment.try(:finalized?)
+
+      if adjustment
+        adjustment.originator = payment_method
+        adjustment.label = adjustment_label
+        adjustment.save
+      else
+        payment_method.create_adjustment(adjustment_label, order, self, true)
+        association(:adjustment).reload
+      end
+    end
+
+    def adjustment_label
+      I18n.t('payment_method_fee')
+    end
+
     private
 
+    # Don't charge fees for invalid or failed payments.
+    # This is called twice for failed payments, because the persistence of the 'failed'
+    # state is acheived through some trickery using an after_rollback callback on the
+    # payment model. See Spree::Payment#persist_invalid
+    def revoke_adjustment_eligibility
+      return unless adjustment.try(:reload)
+      return if adjustment.finalized?
+
+      adjustment.update_attribute(:eligible, false)
+      adjustment.finalize!
+    end
+
     def validate_source
       if source && !source.valid?
         source.errors.each do |field, error|

app/models/spree/payment_decorator.rb

@@ -4,31 +4,11 @@ module Spree
   Payment.class_eval do
     delegate :line_items, to: :order
 
-    has_one :adjustment, as: :source, dependent: :destroy
-
     # We bypass this after_rollback callback that is setup in Spree::Payment
     # The issues the callback fixes are not experienced in OFN:
     #   if a payment fails on checkout the state "failed" is persisted correctly
     def persist_invalid; end
 
-    def ensure_correct_adjustment
-      revoke_adjustment_eligibility if ['failed', 'invalid'].include?(state)
-      return if adjustment.try(:finalized?)
-
-      if adjustment
-        adjustment.originator = payment_method
-        adjustment.label = adjustment_label
-        adjustment.save
-      else
-        payment_method.create_adjustment(adjustment_label, order, self, true)
-        association(:adjustment).reload
-      end
-    end
-
-    def adjustment_label
-      I18n.t('payment_method_fee')
-    end
-
     private
 
     def create_payment_profile
@@ -41,17 +21,5 @@ module Spree
     rescue ActiveMerchant::ConnectionError => e
       gateway_error e
     end
-
-    # Don't charge fees for invalid or failed payments.
-    # This is called twice for failed payments, because the persistence of the 'failed'
-    # state is acheived through some trickery using an after_rollback callback on the
-    # payment model. See Spree::Payment#persist_invalid
-    def revoke_adjustment_eligibility
-      return unless adjustment.try(:reload)
-      return if adjustment.finalized?
-
-      adjustment.update_attribute(:eligible, false)
-      adjustment.finalize!
-    end
   end
 end

spec/models/spree/payment_original_spec.rb

@@ -787,4 +787,35 @@ describe Spree::Payment do
       payment.refund!
     end
   end
+
+  describe "applying transaction fees" do
+    let!(:order) { create(:order) }
+    let!(:line_item) { create(:line_item, order: order, quantity: 3, price: 5.00) }
+
+    before do
+      order.reload.update!
+    end
+
+    context "when order-based calculator" do
+      let!(:shop) { create(:enterprise) }
+      let!(:payment_method) { create(:payment_method, calculator: calculator) }
+
+      let!(:calculator) do
+        Spree::Calculator::FlatPercentItemTotal.new(preferred_flat_percent: 10)
+      end
+
+      context "when order complete and inventory tracking enabled" do
+        let!(:order) { create(:completed_order_with_totals, distributor: shop) }
+        let!(:variant) { order.line_items.first.variant }
+        let!(:inventory_item) { create(:inventory_item, enterprise: shop, variant: variant) }
+
+        it "creates adjustment" do
+          payment = create(:payment, order: order, payment_method: payment_method,
+                           amount: order.total)
+          expect(payment.adjustment).to be_present
+          expect(payment.adjustment.amount).not_to eq(0)
+        end
+      end
+    end
+  end
 end

spec/models/spree/payment_spec.rb

@@ -11,28 +11,6 @@ module Spree
         order.reload.update!
       end
 
-      context "when order-based calculator" do
-        let!(:shop) { create(:enterprise) }
-        let!(:payment_method) { create(:payment_method, calculator: calculator) }
-
-        let!(:calculator) do
-          Spree::Calculator::FlatPercentItemTotal.new(preferred_flat_percent: 10)
-        end
-
-        context "when order complete and inventory tracking enabled" do
-          let!(:order) { create(:completed_order_with_totals, distributor: shop) }
-          let!(:variant) { order.line_items.first.variant }
-          let!(:inventory_item) { create(:inventory_item, enterprise: shop, variant: variant) }
-
-          it "creates adjustment" do
-            payment = create(:payment, order: order, payment_method: payment_method,
-                                       amount: order.total)
-            expect(payment.adjustment).to be_present
-            expect(payment.adjustment.amount).not_to eq(0)
-          end
-        end
-      end
-
       context "to Stripe payments" do
         let(:shop) { create(:enterprise) }
         let(:payment_method) { create(:stripe_payment_method, distributor_ids: [create(:distributor_enterprise).id], preferred_enterprise_id: shop.id) }