Fix Rubocop: Delete dependent stock_movements

.rubocop_todo.yml

@@ -565,17 +565,6 @@ RSpecRails/InferredSpecType:
     - 'spec/requests/voucher_adjustments_spec.rb'
     - 'spec/routing/stripe_spec.rb'
 
-# Offense count: 11
-# Configuration parameters: Include.
-# Include: app/models/**/*.rb
-Rails/HasManyOrHasOneDependent:
-  Exclude:
-    - 'app/models/enterprise.rb'
-    - 'app/models/spree/address.rb'
-    - 'app/models/spree/stock_item.rb'
-    - 'app/models/spree/tax_rate.rb'
-    - 'app/models/spree/variant.rb'
-
 # Offense count: 22
 # Configuration parameters: IgnoreScopes, Include.
 # Include: app/models/**/*.rb

app/models/spree/stock_item.rb

@@ -8,7 +8,7 @@ module Spree
 
     belongs_to :stock_location, class_name: 'Spree::StockLocation', inverse_of: :stock_items
     belongs_to :variant, -> { with_deleted }, class_name: 'Spree::Variant'
-    has_many :stock_movements, dependent: nil
+    has_many :stock_movements, dependent: :destroy
 
     validates :stock_location, :variant, presence: true
     validates :variant_id, uniqueness: { scope: [:stock_location_id, :deleted_at] }

app/models/spree/stock_movement.rb

@@ -14,10 +14,6 @@ module Spree
 
     scope :recent, -> { order('created_at DESC') }
 
-    def readonly?
-      !new_record?
-    end
-
     private
 
     def update_stock_item_quantity

spec/models/spree/stock_item_spec.rb

@@ -109,12 +109,8 @@ RSpec.describe Spree::StockItem do
     context "with stock movements" do
       before { Spree::StockMovement.create(stock_item: subject, quantity: 1) }
 
-      it "doesnt raise ReadOnlyRecord error" do
-        expect { subject.destroy }.not_to raise_error
-      end
-
       it "does not destroy stock_movements when destroyed" do
-        expect { subject.destroy }.not_to change { Spree::StockMovement.count }
+        expect { subject.destroy }.to change { Spree::StockMovement.count }.by(-1)
       end
     end
   end

spec/models/spree/stock_movement_spec.rb

@@ -11,13 +11,6 @@ describe Spree::StockMovement do
     expect(subject).to respond_to(:stock_item)
   end
 
-  it 'is readonly unless new' do
-    subject.save
-    expect {
-      subject.save
-    }.to raise_error(ActiveRecord::ReadOnlyRecord)
-  end
-
   context "when quantity is negative" do
     context "after save" do
       it "should decrement the stock item count on hand" do