do not invoice service with no chargeable item (fix #181)

app/models/service.rb

@@ -243,6 +243,12 @@ class Service < ActiveRecord::Base
     return records if self.first_invoicing_started_on.nil?
     return records if self.service_sale_templates.empty?
 
+    # Ensure at least one service_sale_templates is chargeable
+    if service_sale_templates.where(chargeable: true).empty?
+      errors.add(:base, :no_chargeable_item)
+      return records
+    end
+
     # Ensure that there is no open invoice for this service
     if is_there_an_open_invoice_for_this_service?
       errors.add(:base, :already_an_open_invoice)
@@ -256,6 +262,7 @@ class Service < ActiveRecord::Base
       return records
     end
 
+
     # For services not yet invoiced, set the last_invoicing_end_at to yesterday
     # in order to bill them.
     if last_invoicing_end_at.nil?

config/locales/activerecord.fr.yml

@@ -383,6 +383,7 @@ fr:
           already_a_pending_payment: "Il y a déjà un paiement en attente pour ce service"
           already_an_open_invoice: "Il y a déjà une facture en brouillon pour ce service"
           last_invoicing_end_at_after_end_of_month_chargeable: "La fin de facturation de ce service est postérieur au mois de facturation en cours"
+          no_chargeable_item: "Le service n'a pas d'item facturable"
 
         radio_service:
           <<: *service_errors

spec/models/service_spec.rb

@@ -610,6 +610,18 @@ RSpec.describe Service, type: :model do
       ]
     end
 
+    it 'should not render anything if there is no chargeable item' do
+      @service = FactoryBot.create(
+        :dsl_service,
+        member: @member,
+        first_invoicing_started_on: Date.today - 5.month,
+        last_invoicing_end_at: Date.yesterday - 2.month,
+      )
+      @service.service_sale_templates.update_all(chargeable: false)
+      records = @service.generate_invoicing
+      expect(records).to be_empty
+    end
+
     # it 'should use deposit account if possible' do
     #   @service = FactoryBot.create(
     #     :vpn_service,