Move CodeOcean::FileNameValidator

app/validators/code_ocean/file_name_validator.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module CodeOcean
+  class FileNameValidator < ActiveModel::Validator
+    def validate(record)
+      existing_files = File.where(name: record.name, path: record.path, file_type_id: record.file_type_id,
+        context_id: record.context_id, context_type: record.context_type).to_a
+      if !existing_files.empty? && (!record.context.is_a?(Exercise) || record.context.new_record?)
+        record.errors[:base] << 'Duplicate'
+      end
+    end
+  end
+end