feat: add validation for number of field labels

app/services/bulk_upload/lettings/validator.rb

@@ -9,6 +9,7 @@ class BulkUpload::Lettings::Validator
   attr_reader :bulk_upload, :path
 
   validate :validate_file_not_empty
+  validate :validate_fields_count
   validate :validate_min_columns
   validate :validate_max_columns
 
@@ -145,6 +146,12 @@ private
     errors.add(:base, :over_max_column_count) if column_count > csv_parser.class::MAX_COLUMNS
   end
 
+  def validate_fields_count
+    return if halt_validations?
+
+    errors.add(:base, :wrong_field_count) if csv_parser.non_blank_fields_count != csv_parser.class::FIELDS
+  end
+
   def halt_validations!
     @halt_validations = true
   end

app/services/bulk_upload/lettings/year2023/csv_parser.rb

@@ -3,6 +3,7 @@ require "csv"
 class BulkUpload::Lettings::Year2023::CsvParser
   MIN_COLUMNS = 141
   MAX_COLUMNS = 143
+  FIELDS = 134
 
   attr_reader :path
 
@@ -47,6 +48,10 @@ class BulkUpload::Lettings::Year2023::CsvParser
     cols[field_numbers.find_index(field) + col_offset]
   end
 
+  def non_blank_fields_count
+    field_numbers.count { |f| f != "field_blank" }
+  end
+
 private
 
   def default_field_numbers

config/locales/en.yml

@@ -46,6 +46,7 @@ en:
             base:
               over_max_column_count: "too many columns, please ensure you have used the correct template"
               under_min_column_count: "too few columns, please ensure you have used the correct template"
+              wrong_field_count: "incorrect number of fields, please ensure you have used the correct template"
         forms/bulk_upload_lettings/year:
           attributes:
             year: