Merge pull request #3563 from kristinalim/fix/3562-fix_payment_fee_for_order_based_calculator

3562 Fix error calculating payment fee using order-based calculator

app/models/spree/payment_decorator.rb

@@ -4,6 +4,8 @@ module Spree
   Payment.class_eval do
     extend Spree::LocalizedNumber
 
+    delegate :line_items, to: :order
+
     has_one :adjustment, as: :source, dependent: :destroy
 
     after_save :ensure_correct_adjustment, :update_order
@@ -30,15 +32,6 @@ module Spree
       I18n.t('payment_method_fee')
     end
 
-    # This is called by the calculator of a payment method
-    def line_items
-      if order.complete? && Spree::Config[:track_inventory_levels]
-        order.line_items.select { |li| inventory_units.pluck(:variant_id).include?(li.variant_id) }
-      else
-        order.line_items
-      end
-    end
-
     # Pin payments lacks void and credit methods, but it does have refund
     # Here we swap credit out for refund and remove void as a possible action
     def actions_with_pin_payment_adaptations

spec/models/spree/payment_spec.rb

@@ -133,6 +133,28 @@ 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) }