enable updating org rent periods

update logic in #update
related tests

app/controllers/organisations_controller.rb

@@ -115,6 +115,7 @@ class OrganisationsController < ApplicationController
   end
 
   def update
+    selected_rent_periods = params.require(:organisation).permit(rent_periods: [])[:rent_periods].compact_blank
     if (current_user.data_coordinator? && org_params[:active].nil?) || current_user.support?
       if @organisation.update(org_params)
         case org_params[:active]
@@ -133,7 +134,17 @@ class OrganisationsController < ApplicationController
         else
           flash[:notice] = I18n.t("organisation.updated")
         end
+        existing_rent_periods = @organisation.organisation_rent_periods.map(&:rent_period)
+        rent_periods_to_create = selected_rent_periods.map(&:to_i) - existing_rent_periods
+        rent_periods_to_delete = existing_rent_periods - selected_rent_periods.map(&:to_i)
+        OrganisationRentPeriod.transaction do
+          rent_periods_to_create.each { |period| OrganisationRentPeriod.create!(organisation: @organisation, rent_period: period) }
+          OrganisationRentPeriod.where(organisation: @organisation, rent_period: rent_periods_to_delete).destroy_all
+        end
         redirect_to details_organisation_path(@organisation)
+      else
+        @rent_periods = helpers.rent_periods_with_checked_attr(checked_periods: selected_rent_periods)
+        render :edit, status: :unprocessable_entity
       end
     else
       head :unauthorized

spec/requests/OrganisationsController/organisations_controller_rent_periods_spec.rb

@@ -80,4 +80,40 @@ RSpec.describe OrganisationsController, type: :request do
       expect(expected_not_checked_checkbox[:checked]).to be false
     end
   end
+
+  describe "#update" do
+    let(:organisation) { create(:organisation) }
+    let(:initially_checked_rent_period_id) { "1" }
+    let(:initially_unchecked_rent_period_id) { "2" }
+    let(:fake_rent_periods) do
+      {
+        initially_checked_rent_period_id => { "value" => "Every minute" },
+        initially_unchecked_rent_period_id => { "value" => "Every decade" },
+      }
+    end
+    let(:params) do
+      {
+        "organisation": {
+          name: organisation.name,
+          rent_periods: [initially_unchecked_rent_period_id],
+        },
+      }
+    end
+
+    before do
+      create(:organisation_rent_period, organisation:, rent_period: initially_checked_rent_period_id)
+    end
+
+    it "creates and destroys organisation rent periods as appropriate" do
+      rent_periods = OrganisationRentPeriod.all
+      expect(rent_periods.count).to be 1
+      expect(rent_periods.first.rent_period.to_s).to eq initially_checked_rent_period_id
+
+      patch organisation_path(organisation, headers:, params:)
+
+      rent_periods = OrganisationRentPeriod.all
+      expect(rent_periods.count).to be 1
+      expect(rent_periods.first.rent_period.to_s).to eq initially_unchecked_rent_period_id
+    end
+  end
 end