Reference value constants from specs (#33479)

spec/policies/backup_policy_spec.rb

@@ -23,22 +23,30 @@ RSpec.describe BackupPolicy do
 
       context 'when backups are too old' do
         it 'permits' do
-          travel(-8.days) do
+          travel(-before_time) do
             Fabricate(:backup, user: john.user)
           end
 
           expect(subject).to permit(john, Backup)
         end
+
+        def before_time
+          described_class::MIN_AGE + 2.days
+        end
       end
 
       context 'when backups are newer' do
         it 'denies' do
-          travel(-3.days) do
+          travel(-within_time) do
             Fabricate(:backup, user: john.user)
           end
 
           expect(subject).to_not permit(john, Backup)
         end
+
+        def within_time
+          described_class::MIN_AGE - 2.days
+        end
       end
     end
   end