def METHOD_NAME(self):
    """test for max length"""
    # get object
    system_1 = System.objects.get(system_name='system_1')
    # get object
    systemhistory_1 = Systemhistory.objects.filter(
        system=system_1.system_id
    ).order_by('-systemhistory_id')[0]
    # get max length
    max_length = systemhistory_1._meta.get_field(
        'systemhistory_new_value'
    ).max_length
    # compare
    self.assertEqual(max_length, 255)