new_contents: import unittest
  from django_enumfield.tests.models import BeerStyle
  from django_enumfield.validators import validate_available_choice
  from django_enumfield.exceptions import InvalidStatusOperationError
  
  
  class ValidatorTest(unittest.TestCase):
      def test_validate_available_choice_1(self):
          """Test passing a value non convertable to an int raises an
          InvalidStatusOperationError
          """
          self.assertRaises(
              InvalidStatusOperationError,
              validate_available_choice,
              *(BeerStyle, 'Not an int')
          )
  
      def test_validate_available_choice_2(self):
          """Test passing an int as a string validation
          """
          self.assertIsNone(
              validate_available_choice(BeerStyle, '%s' % BeerStyle.LAGER)
          )
  
      def test_validate_available_choice_3(self):
          """Test passing an int validation
          """
          self.assertIsNone(
              validate_available_choice(BeerStyle, BeerStyle.LAGER)
          )
  
subject: Add tests