Add scenario to RelatedContent model spec to check opposite related content creation

spec/models/relation_spec.rb

@@ -23,4 +23,19 @@ describe RelatedContent do
     expect(new_related_content).not_to be_valid
   end
 
+  describe 'create_opposite_related_content' do
+    let(:parent_relationable) { create(:proposal) }
+    let(:child_relationable) { create(:debate) }
+    let(:related_content) { build(:related_content, parent_relationable: parent_relationable, child_relationable: child_relationable) }
+
+    it 'creates an opposite related_content' do
+      expect { related_content.save }.to change { RelatedContent.count }.by(2)
+      expect(related_content.opposite_related_content.child_relationable_id).to eq(parent_relationable.id)
+      expect(related_content.opposite_related_content.child_relationable_type).to eq(parent_relationable.class.name)
+      expect(related_content.opposite_related_content.parent_relationable_id).to eq(child_relationable.id)
+      expect(related_content.opposite_related_content.parent_relationable_type).to eq(child_relationable.class.name)
+      expect(related_content.opposite_related_content.opposite_related_content.id).to eq(related_content.id)
+    end
+  end
+
 end