fix: move annotation and listing changes to CitesCop and EuRegulation…

… models, as they have different potential behaviours

app/models/event.rb

@@ -41,8 +41,6 @@ class Event < ApplicationRecord
   attr_reader :effective_at_formatted
 
   belongs_to :designation, optional: true
-  has_many :listing_changes, dependent: :destroy
-  has_many :annotations, dependent: :destroy
   has_many :documents
   has_many :cites_processes
 

app/models/events/cites_cop.rb

@@ -36,6 +36,16 @@ class CitesCop < Event
   # Migrated to controller (Strong Parameters)
   # attr_accessible :is_current
 
+  ##
+  # The only time we would delete a CoP/EU regulation is just after we've
+  # created it by mistake, but we don't want to be able to delete the CoP
+  # event once it's started to be populated, whereas an EU Regulation
+  # starts off being populated with lots of associated data so we can't
+  # restrict deletion.
+  has_many :listing_changes,
+    dependent: :restrict_with_error,
+    foreign_key: :event_id
+
   has_many :hash_annotations,
     class_name: 'Annotation',
     dependent: :destroy,

app/models/events/eu_regulation.rb

@@ -37,6 +37,20 @@ class EuRegulation < EuEvent
   # attr_accessible :listing_changes_event_id, :end_date
   attr_accessor :listing_changes_event_id
 
+  ##
+  # The only time we would delete a CoP/EU regulation is just after we've
+  # created it by mistake, but we don't want to be able to delete the CoP
+  # event once it's started to be populated, whereas an EU Regulation
+  # starts off being populated with lots of associated data so we can't
+  # restrict deletion.
+  has_many :listing_changes,
+    dependent: :destroy,
+    foreign_key: :event_id
+
+  has_many :annotations,
+    dependent: :destroy,
+    foreign_key: :event_id
+
   validate :designation_is_eu
   validates :effective_at, presence: true
 

spec/models/events/cites_cop_spec.rb

@@ -51,14 +51,44 @@
 
   describe :destroy do
     let(:cites_cop) { create_cites_cop }
+
     context 'when no dependent objects attached' do
       specify { expect(cites_cop.destroy).to be_truthy }
     end
+
     context 'when dependent objects attached' do
-      context 'when listing changes' do
+      ##
+      # NB: deleting EU regulation events will cause all its listing changes to
+      # be deleted, whereas CITES CoPs will refuse to be deleted until its
+      # listing changes are deleted.
+      context 'when listing changes exist' do
         let!(:listing_change) { create_cites_I_addition(event: cites_cop) }
         specify { expect(cites_cop.destroy).to be_falsey }
       end
+
+      context 'when listing change and annotation' do
+        let!(:annotation) { create(:annotation, event: cites_cop) }
+        let!(:listing_change) do
+          create_cites_I_addition(
+            event: cites_cop,
+            annotation: annotation
+          )
+        end
+
+        specify { expect(cites_cop.destroy).to be_falsey }
+      end
+
+      context 'when listing change and hash annotation' do
+        let!(:hash_annotation) { create(:annotation, event: cites_cop) }
+        let!(:listing_change) do
+          create_cites_I_addition(
+            event: cites_cop,
+            hash_annotation: hash_annotation
+          )
+        end
+
+        specify { expect(cites_cop.destroy).to be_falsey }
+      end
     end
   end
 end

spec/models/events/eu_regulation_spec.rb

@@ -78,14 +78,44 @@
 
   describe :destroy do
     let(:eu_regulation) { create_eu_regulation }
+
     context 'when no dependent objects attached' do
       specify { expect(eu_regulation.destroy).to be_truthy }
     end
+
     context 'when dependent objects attached' do
+      ##
+      # NB: deleting EU regulation events will cause all its listing changes to
+      # be deleted, whereas CITES CoPs will refuse to be deleted until its
+      # listing changes are deleted.
       context 'when listing changes' do
         let!(:listing_change) { create_eu_A_addition(event: eu_regulation) }
         specify { expect(eu_regulation.destroy).to be_truthy }
       end
+
+      context 'when listing change and annotation' do
+        let!(:annotation) { create(:annotation, event: eu_regulation) }
+        let!(:listing_change) do
+          create_eu_A_addition(
+            event: eu_regulation,
+            annotation: annotation
+          )
+        end
+
+        specify { expect(eu_regulation.destroy).to be_truthy }
+      end
+
+      context 'when listing change and hash annotation' do
+        let!(:hash_annotation) { create(:annotation, event: eu_regulation) }
+        let!(:listing_change) do
+          create_eu_A_addition(
+            event: eu_regulation,
+            hash_annotation: hash_annotation
+          )
+        end
+
+        specify { expect(eu_regulation.destroy).to be_truthy }
+      end
     end
   end
 end