def test_g(self):
        """Test a watertype references the new WatertypeGroup."""
        watertype = KRWWatertype()
        watertype.code = 'O1'
        watertype.save()

        WatertypeGroups().create('K&O')

        watertype = KRWWatertype.objects.get(code='O1')
        self.assertEqual(WatertypeGroup.objects.get(code='K&O'), watertype.watertype_group)
    def test_c(self):
        """Test a watertype does not reference the new WatertypeGroup."""
        watertype = KRWWatertype()
        watertype.code = 'R1'
        watertype.save()

        WatertypeGroups().create('M')

        watertype = KRWWatertype.objects.get(code='R1')
        self.assertEqual(None, watertype.watertype_group)