CLDC-4175: add reverse validation

app/models/validations/sales/financial_validations.rb

@@ -154,6 +154,7 @@ module Validations::Sales::FinancialValidations
 
     if record.newservicecharges == record.mscharge
       record.errors.add :newservicecharges, I18n.t("validations.sales.financial.newservicecharges.same_as_previous")
+      record.errors.add :mscharge, I18n.t("validations.sales.financial.mscharge.same_as_new")
     end
   end
 

config/locales/validations/sales/financial.en.yml

@@ -48,6 +48,7 @@ en:
         mscharge:
           monthly_leasehold_charges:
             not_zero: "Monthly leasehold charges cannot be £0 if the property has monthly charges."
+          same_as_new: "You said that the service charge will change and you entered the same amount as the new service charge. If the service charge will not change, answer 'No' to 'Will the service charge change after this staircasing transaction takes place?'."
 
         newservicecharges:
           negative: "Service charge cannot be negative."

spec/models/validations/sales/financial_validations_spec.rb

@@ -568,6 +568,7 @@ RSpec.describe Validations::Sales::FinancialValidations do
       record.mscharge = 100
       financial_validator.validate_newservicecharges_different_from_mscharge(record)
       expect(record.errors["newservicecharges"]).to include(match I18n.t("validations.sales.financial.newservicecharges.same_as_previous"))
+      expect(record.errors["mscharge"]).to include(match I18n.t("validations.sales.financial.mscharge.same_as_new"))
     end
   end
 end