Memoise lettings forms in form handler (#1845)

* feat: memoise lettings forms

* feat: update tests

app/models/form_handler.rb

@@ -75,6 +75,10 @@ class FormHandler
   end
 
   def lettings_forms
+    @lettings_forms ||= get_lettings_forms
+  end
+
+  def get_lettings_forms
     forms = {}
     directories.each do |directory|
       Dir.glob("#{directory}/*.json").each do |form_path|
@@ -154,6 +158,7 @@ class FormHandler
 
   def use_real_forms!
     @directories = ["config/forms"]
+    @lettings_forms = get_lettings_forms
     @forms = get_all_forms
   end
 

spec/models/form_spec.rb

@@ -188,7 +188,6 @@ RSpec.describe Form, type: :model do
 
       around do |example|
         FormHandler.instance.use_real_forms!
-
         example.run
       end
 

spec/models/lettings_log_spec.rb

@@ -1575,6 +1575,7 @@ RSpec.describe LettingsLog do
       it "clears underoccupation_benefitcap if log is no longer in 2021/22" do
         expect { lettings_log.update!(renewal: 1) }.to change(lettings_log, :underoccupation_benefitcap).to 2
         Timecop.return
+        Singleton.__init__(FormHandler)
         expect { lettings_log.update!(startdate: Time.zone.local(2023, 1, 1)) }.to change(lettings_log, :underoccupation_benefitcap).from(2).to nil
       end
 
@@ -2040,6 +2041,7 @@ RSpec.describe LettingsLog do
 
         before do
           Timecop.freeze(Time.zone.local(2022, 4, 2))
+          Singleton.__init__(FormHandler)
           lettings_log.update!(startdate: Time.zone.local(2022, 4, 2), scheme:)
           Timecop.unfreeze
         end