Remove Order#set_payment_amount!

app/models/spree/order.rb

@@ -734,16 +734,5 @@ module Spree
       adjustment.update_adjustment!(force: true)
       updater.update_totals_and_states
     end
-
-    # object_params sets the payment amount to the order total, but it does this
-    # before the shipping method is set. This results in the customer not being
-    # charged for their order's shipping. To fix this, we refresh the payment
-    # amount here.
-    def set_payment_amount!
-      update_totals
-      return unless pending_payments.any?
-
-      pending_payments.first.update_attribute :amount, total
-    end
   end
 end

app/models/spree/order/checkout.rb

@@ -81,7 +81,6 @@ module Spree
               after_transition to: :complete, do: :finalize!
               after_transition to: :resumed,  do: :after_resume
               after_transition to: :canceled, do: :after_cancel
-              after_transition to: :payment, do: :set_payment_amount!
             end
           end
 

spec/models/spree/order_spec.rb

@@ -1335,54 +1335,6 @@ describe Spree::Order do
     end
   end
 
-  describe '#set_payment_amount!' do
-    let(:order) do
-      shipment = build(:shipment_with, :shipping_method, shipping_method: build(:shipping_method))
-      build(:order, shipments: [shipment])
-    end
-
-    context 'after transitioning to payment' do
-      before do
-        order.state = 'delivery' # payment's previous state
-
-        allow(order).to receive(:payment_required?) { true }
-      end
-
-      it 'calls #set_payment_amount! and updates totals' do
-        expect(order).to receive(:set_payment_amount!)
-        expect(order).to receive(:update_totals).at_least(:once)
-
-        order.next
-      end
-
-      context "payment's amount" do
-        let(:failed_payment) { create(:payment, order: order, state: 'failed', amount: 100) }
-
-        before do
-          allow(order).to receive(:total) { 120 }
-        end
-
-        it 'is not updated for failed payments' do
-          failed_payment
-
-          order.next
-
-          expect(failed_payment.reload.amount).to eq 100
-        end
-
-        it 'is updated only for pending payments' do
-          pending_payment = create(:payment, order: order, state: 'pending', amount: 80)
-          failed_payment
-
-          order.next
-
-          expect(failed_payment.reload.amount).to eq 100
-          expect(pending_payment.reload.amount).to eq 120
-        end
-      end
-    end
-  end
-
   describe "#ensure_updated_shipments" do
     before { Spree::Shipment.create!(order: order) }