test: check managing org not gone from answer opts when relationship deleted

spec/models/form/lettings/questions/managing_organisation_spec.rb

@@ -135,6 +135,28 @@ RSpec.describe Form::Lettings::Questions::ManagingOrganisation, type: :model do
         expect(question.displayed_answer_options(log, user)).to eq(options)
       end
     end
+
+    context "when the owning-managing organisation relationship is deleted" do
+      let(:user) { create(:user, :support) }
+      let(:owning_org) { create(:organisation, name: "OwningOrg", holds_own_stock: true) }
+      let(:managing_org) { create(:organisation, name: "ManagingOrg", holds_own_stock: false) }
+      let!(:org_rel) { create(:organisation_relationship, parent_organisation: owning_org, child_organisation: managing_org) }
+      let(:log) { create(:lettings_log, owning_organisation: owning_org, managing_organisation: managing_org) }
+
+      let(:options) do
+        {
+          "" => "Select an option",
+          owning_org.id => "OwningOrg (Owning organisation)",
+          managing_org.id => "ManagingOrg",
+        }
+      end
+
+      it "doesn't remove the managing org from the list of allowed managing orgs" do
+        org_rel.destroy!
+        expect(question.displayed_answer_options(log, user)).to eq(options)
+      end
+    end
+
   end
 
   it "is marked as derived" do