Create RelatedContent model spec to check relationable destroy

app/models/concerns/relationable.rb

@@ -2,6 +2,6 @@ module Relationable
   extend ActiveSupport::Concern
 
   included do
-    has_many :related_contents, as: :parent_relationable
+    has_many :related_contents, as: :parent_relationable, dependent: :destroy
   end
 end

app/models/related_content.rb

@@ -10,6 +10,7 @@ class RelatedContent < ActiveRecord::Base
   validates :parent_relationable_id, uniqueness: { scope: [:parent_relationable_type, :child_relationable_id, :child_relationable_type] }
 
   after_create :create_opposite_related_content, unless: proc { opposite_related_content.present? }
+  after_destroy :destroy_opposite_related_content, if: proc { opposite_related_content.present? }
 
   private
 
@@ -18,4 +19,7 @@ class RelatedContent < ActiveRecord::Base
     self.opposite_related_content = related_content
   end
 
+  def destroy_opposite_related_content
+    opposite_related_content.destroy
+  end
 end

spec/models/relation_spec.rb

@@ -38,4 +38,14 @@ describe RelatedContent do
     end
   end
 
+  describe 'relationable destroy' do
+    let(:parent_relationable) { create(:proposal) }
+    let(:child_relationable) { create(:debate) }
+
+    it 'destroys both related contents involved' do
+      related_content = create(:related_content, parent_relationable: parent_relationable, child_relationable: child_relationable)
+      expect { related_content.parent_relationable.destroy }.to change { RelatedContent.all.count }.by(-2)
+      expect(child_relationable.related_contents).to be_empty
+    end
+  end
 end