add other reason left settled home validation

app/models/case_log.rb

@@ -15,6 +15,16 @@ class CaseLogValidator < ActiveModel::Validator
     end
   end
 
+  def validate_other_reason_for_leaving_last_settled_home(record)
+    if record.reason_for_leaving_last_settled_home == "Other" && record.other_reason_for_leaving_last_settled_home.blank?
+      record.errors.add :other_reason_for_leaving_last_settled_home, "If reason for leaving settled home is other then the other reason must be provided"
+    end
+
+    if record.reason_for_leaving_last_settled_home != "Other" && record.other_reason_for_leaving_last_settled_home.present?
+      record.errors.add :other_reason_for_leaving_last_settled_home, "The other reason must not be provided if the reason for leaving settled home was not other"
+    end
+  end
+
   def validate(record)
     # If we've come from the form UI we only want to validate the specific fields
     # that have just been submitted. If we're submitting a log via API or Bulk Upload

spec/models/case_log_spec.rb

@@ -25,6 +25,22 @@ RSpec.describe Form, type: :model do
     it "validates number of relets is over 0" do
       expect { CaseLog.create!(property_number_of_times_relet: 0) }.to raise_error(ActiveRecord::RecordInvalid)
     end
+
+    context "other reason for leaving last settled home validation" do
+      it "must be provided if main reason for leaving last settled home was given as other" do
+        expect {
+          CaseLog.create!(reason_for_leaving_last_settled_home: "Other",
+                          other_reason_for_leaving_last_settled_home: nil)
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+
+      it "must not be provided if the main reason for leaving settled home is not other" do
+        expect {
+          CaseLog.create!(reason_for_leaving_last_settled_home: "Repossession",
+                          other_reason_for_leaving_last_settled_home: "the other reason provided")
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+    end
   end
 
   describe "status" do