49: def validate_only(key)
50: validation_name, attribute_name = key.split("/")
51: validation_name = validation_name.split("_").collect{|word| word.capitalize}.join
52: validation_key = "#{self.class.name}/Validatable::Validates#{validation_name}/#{attribute_name}"
53: validation = self.class.all_validations.find { |validation| validation.key == validation_key }
54: raise ArgumentError.new("validation with key #{validation_key} could not be found") if validation.nil?
55: errors.clear
56: run_validation(validation)
57: end