Ensure order association is set correctly when adding admin adjustments

app/controllers/spree/admin/adjustments_controller.rb

@@ -5,6 +5,7 @@ module Spree
       destroy.after :reload_order
 
       prepend_before_action :set_included_tax, only: [:create, :update]
+      before_action :set_order_id, only: [:create, :update]
       before_action :set_default_tax_rate, only: :edit
       before_action :enable_updates, only: :update
 
@@ -22,6 +23,10 @@ module Spree
         parent.all_adjustments.eligible.find(params[:id])
       end
 
+      def set_order_id
+        @adjustment.order_id = parent.id
+      end
+
       # Choose a default tax rate to show on the edit form. The adjustment stores its included
       # tax in dollars, but doesn't store the source of the tax (ie. TaxRate that generated it).
       # We guess which tax rate here, choosing:

spec/controllers/spree/admin/adjustments_controller_spec.rb

@@ -21,6 +21,7 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(0)
+          expect(a.order_id).to eq(order.id)
         end
 
         it "calculates included tax when a tax rate is provided" do
@@ -31,6 +32,7 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(10)
+          expect(a.order_id).to eq(order.id)
         end
       end
 
@@ -47,6 +49,7 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(0)
+          expect(a.order_id).to eq(order.id)
         end
 
         it "calculates included tax when a tax rate is provided" do
@@ -57,6 +60,7 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(10)
+          expect(a.order_id).to eq(order.id)
         end
       end
     end