CLDC-3870: Ask number of bedrooms when changing answer to non bedsit (#3123)

* CLDC-3870: Nil the beds question when the user changes off of bedsit

this forces the user to answer it again as we previously assumed the answer to be '1' when they answered bedsit

* CLDC-3870: Add tests

app/models/derived_variables/lettings_log_variables.rb

@@ -71,6 +71,9 @@ module DerivedVariables::LettingsLogVariables
     if form.start_year_2024_or_later? && is_bedsit?
       self.beds = 1
     end
+    if bedsit_changed_to_not_bedsit? # make user answer num of bedrooms again
+      self.beds = nil
+    end
 
     clear_child_ecstat_for_age_changes!
     child_under_16_constraints!

app/models/derived_variables/sales_log_variables.rb

@@ -83,6 +83,9 @@ module DerivedVariables::SalesLogVariables
     if form.start_year_2025_or_later? && is_bedsit?
       self.beds = 1
     end
+    if bedsit_changed_to_not_bedsit? # make user answer num of bedrooms again
+      self.beds = nil
+    end
 
     self.nationality_all = nationality_all_group if nationality_uk_or_prefers_not_to_say?
     self.nationality_all_buyer2 = nationality_all_buyer2_group if nationality2_uk_or_prefers_not_to_say?

app/models/lettings_log.rb

@@ -399,6 +399,10 @@ class LettingsLog < Log
     form.start_year_2024_or_later? && is_bedsit?
   end
 
+  def bedsit_changed_to_not_bedsit?
+    unittype_gn_changed? && unittype_gn_was == 2
+  end
+
   def is_shared_housing?
     # 4: Shared flat or maisonette
     # 9: Shared house

app/models/sales_log.rb

@@ -386,6 +386,10 @@ class SalesLog < Log
     form.start_year_2025_or_later? && is_bedsit?
   end
 
+  def bedsit_changed_to_not_bedsit?
+    proptype_changed? && proptype_was == 2
+  end
+
   def shared_ownership_scheme?
     ownershipsch == 1
   end

spec/models/lettings_log_derived_fields_spec.rb

@@ -1232,4 +1232,20 @@ RSpec.describe LettingsLog, type: :model do
       expect { log.set_derived_fields! }.to not_change(log, :ecstat2)
     end
   end
+
+  describe "deriving num of bedrooms from whether property is bedsit" do
+    it "sets num of bedrooms to 1 when property is a bedsit" do
+      log.unittype_gn = 2
+      expect { log.set_derived_fields! }.to change(log, :beds).to 1
+    end
+
+    it "sets num of bedrooms to nil when property is change from a bedsit" do
+      log.unittype_gn = 2
+      log.set_derived_fields!
+      log.clear_changes_information
+
+      log.unittype_gn = 1
+      expect { log.set_derived_fields! }.to change(log, :beds).to nil
+    end
+  end
 end

spec/models/sales_log_derived_fields_spec.rb

@@ -186,5 +186,23 @@ RSpec.describe SalesLog, type: :model do
         end
       end
     end
+
+    describe "deriving num of bedrooms from whether property is bedsit" do
+      let(:log) { create(:sales_log, :completed) }
+
+      it "sets num of bedrooms to 1 when property is a bedsit" do
+        log.proptype = 2
+        expect { log.set_derived_fields! }.to change(log, :beds).to 1
+      end
+
+      it "sets num of bedrooms to nil when property is change from a bedsit" do
+        log.proptype = 2
+        log.set_derived_fields!
+        log.clear_changes_information
+
+        log.proptype = 1
+        expect { log.set_derived_fields! }.to change(log, :beds).to nil
+      end
+    end
   end
 end