add compound validation to ensure that logs of type older person shared ownership may not have a stairbought value of greater than 75% \n associated tests included

app/models/sales_log.rb

@@ -136,6 +136,10 @@ class SalesLog < Log
     type == 18
   end
 
+  def is_older_persons_shared_ownership?
+    type == 24
+  end
+
   def ppostcode_full=(postcode)
     if postcode
       super UKPostcode.parse(postcode).to_s

app/models/validations/sales/financial_validations.rb

@@ -35,4 +35,13 @@ module Validations::Sales::FinancialValidations
       record.errors.add :stairowned, I18n.t("validations.financial.staircasing.percentage_bought_must_be_greater_than_percentage_owned")
     end
   end
+
+  def validate_percentage_owned_not_too_much_if_older_person(record)
+    return unless record.is_older_persons_shared_ownership? && record.stairowned
+
+    if record.stairowned > 75
+      record.errors.add :stairowned, I18n.t("validations.financial.staircasing.older_person_percentage_owned_maximum_75")
+      record.errors.add :type, I18n.t("validations.financial.staircasing.older_person_percentage_owned_maximum_75")
+    end
+  end
 end

config/locales/en.yml

@@ -279,6 +279,7 @@ en:
       cash_discount_invalid: "Cash discount must be £0 - £999,999"
       staircasing:
         percentage_bought_must_be_greater_than_percentage_owned: "Total percentage buyer now owns must be more than percentage bought in this transaction"
+        older_person_percentage_owned_maximum_75: "Percentage cannot be above 75% under Older Person's Shared Ownership"
 
     household:
       reasonpref:

spec/models/validations/sales/financial_validations_spec.rb

@@ -126,4 +126,36 @@ RSpec.describe Validations::Sales::FinancialValidations do
       expect(record.errors["stairowned"]).to include(match I18n.t("validations.financial.staircasing.percentage_bought_must_be_greater_than_percentage_owned"))
     end
   end
+
+  describe "#validate_percentage_owned_not_too_much_if_older_person" do
+    let(:record) { FactoryBot.create(:sales_log) }
+
+    context "when log type is not older persons shared ownership" do
+      it "does not add an error when percentage owned after staircasing transaction exceeds 75%" do
+        record.type = 2
+        record.stairowned = 80
+        financial_validator.validate_percentage_owned_not_too_much_if_older_person(record)
+        expect(record.errors["stairowned"]).to be_empty
+        expect(record.errors["type"]).to be_empty
+      end
+    end
+
+    context "when log type is older persons shared ownership" do
+      it "does not add an error when percentage owned after staircasing transaction is less than 75%" do
+        record.type = 24
+        record.stairowned = 50
+        financial_validator.validate_percentage_owned_not_too_much_if_older_person(record)
+        expect(record.errors["stairowned"]).to be_empty
+        expect(record.errors["type"]).to be_empty
+      end
+
+      it "adds an error when percentage owned after staircasing transaction exceeds 75%" do
+        record.type = 24
+        record.stairowned = 90
+        financial_validator.validate_percentage_owned_not_too_much_if_older_person(record)
+        expect(record.errors["stairowned"]).to include(match I18n.t("validations.financial.staircasing.older_person_percentage_owned_maximum_75"))
+        expect(record.errors["type"]).to include(match I18n.t("validations.financial.staircasing.older_person_percentage_owned_maximum_75"))
+      end
+    end
+  end
 end