Remove use of :source polymorphic association for return adjustments

app/models/spree/adjustment.rb

@@ -66,7 +66,7 @@ module Spree
     scope :optional, -> { where(mandatory: false) }
     scope :charge, -> { where('amount >= 0') }
     scope :credit, -> { where('amount < 0') }
-    scope :return_authorization, -> { where(source_type: "Spree::ReturnAuthorization") }
+    scope :return_authorization, -> { where(originator_type: "Spree::ReturnAuthorization") }
     scope :inclusive, -> { where(included: true) }
     scope :additional, -> { where(included: false) }
 

spec/models/spree/adjustment_spec.rb

@@ -9,7 +9,7 @@ module Spree
 
     describe "scopes" do
       let!(:arbitrary_adjustment) { create(:adjustment, source: nil, label: "Arbitrary") }
-      let!(:return_authorization_adjustment) { create(:adjustment, source: create(:return_authorization)) }
+      let!(:return_authorization_adjustment) { create(:adjustment, originator: create(:return_authorization)) }
 
       it "returns return_authorization adjustments" do
         expect(Spree::Adjustment.return_authorization.to_a).to eq [return_authorization_adjustment]

spec/models/spree/return_authorization_spec.rb

@@ -82,11 +82,15 @@ describe Spree::ReturnAuthorization do
 
     it "should add credit for specified amount" do
       return_authorization.amount = 20
-      mock_adjustment = double
-      expect(mock_adjustment).to receive(:source=).with(return_authorization)
-      expect(mock_adjustment).to receive(:adjustable=).with(order)
-      expect(mock_adjustment).to receive(:save)
-      expect(Spree::Adjustment).to receive(:new).with(amount: -20, label: Spree.t(:rma_credit)).and_return(mock_adjustment)
+
+      expect(Spree::Adjustment).to receive(:create).with(
+        amount: -20,
+        label: I18n.t('spree.rma_credit'),
+        order: order,
+        adjustable: order,
+        originator: return_authorization
+      )
+
       return_authorization.receive!
     end