Reset partial postcodes after setting the main postcode field and add tests

app/models/case_log.rb

@@ -190,10 +190,6 @@ private
   end
 
   def set_derived_fields
-    if property_postcode.present?
-      self.postcode = UKPostcode.parse(property_postcode).outcode
-      self.postcod2 = UKPostcode.parse(property_postcode).incode
-    end
     if previous_postcode.present?
       self.ppostc1 = UKPostcode.parse(previous_postcode).outcode
       self.ppostc2 = UKPostcode.parse(previous_postcode).incode
@@ -218,7 +214,12 @@ private
     else
       self.la = get_la(property_postcode)
     end
-
+    if property_postcode.present?
+      self.postcode = UKPostcode.parse(property_postcode).outcode
+      self.postcod2 = UKPostcode.parse(property_postcode).incode
+    else
+      self.postcode = self.postcod2 = nil
+    end
     self.totchild = get_totchild
     self.totelder = get_totelder
     self.totadult = get_totadult

spec/models/case_log_spec.rb

@@ -1044,14 +1044,18 @@ RSpec.describe Form, type: :model do
         expect(record_from_db["la"]).to eq("E08000003")
       end
 
-      it "correctly resets all fields" do
+      it "correctly resets all fields if property postcode is empty" do
+        address_case_log.update!({ property_postcode: "" })
         address_case_log.reload
 
-        record_from_db = ActiveRecord::Base.connection.execute("select la from case_logs where id=#{address_case_log.id}").to_a[0]
+        record_from_db = ActiveRecord::Base.connection.execute("select la, property_postcode from case_logs where id=#{address_case_log.id}").to_a[0]
-        expect(address_case_log.la).to eq("Manchester")
+        expect(record_from_db["property_postcode"]).to eq(nil)
-        expect(record_from_db["la"]).to eq("E08000003")
+        expect(address_case_log.la).to eq(nil)
+        expect(record_from_db["la"]).to eq(nil)
+      end
 
-        address_case_log.update!({ property_postcode: "" })
+      it "correctly resets all fields if property postcode not known" do
+        address_case_log.update!({ postcode_known: "No" })
         address_case_log.reload
 
         record_from_db = ActiveRecord::Base.connection.execute("select la, property_postcode from case_logs where id=#{address_case_log.id}").to_a[0]
@@ -1059,6 +1063,25 @@ RSpec.describe Form, type: :model do
         expect(address_case_log.la).to eq(nil)
         expect(record_from_db["la"]).to eq(nil)
       end
+
+      it "keeps the LA if property postcode changes from not known to known and not provided" do
+        address_case_log.update!({ postcode_known: "No" })
+        address_case_log.update!({ la: "Westminster" })
+        address_case_log.reload
+
+        record_from_db = ActiveRecord::Base.connection.execute("select la, property_postcode from case_logs where id=#{address_case_log.id}").to_a[0]
+        expect(record_from_db["property_postcode"]).to eq(nil)
+        expect(address_case_log.la).to eq("Westminster")
+        expect(record_from_db["la"]).to eq("E09000033")
+
+        address_case_log.update!({ postcode_known: "Yes" })
+        address_case_log.reload
+
+        record_from_db = ActiveRecord::Base.connection.execute("select la, property_postcode from case_logs where id=#{address_case_log.id}").to_a[0]
+        expect(record_from_db["property_postcode"]).to eq(nil)
+        expect(address_case_log.la).to eq("Westminster")
+        expect(record_from_db["la"]).to eq("E09000033")
+      end
     end
 
     context "household members derived vars" do