def METHOD_NAME(self):
    data = {'ethernet': self.eth.id}
    url = reverse('ipaddress-detail', args=(self.ip_with_dhcp.id,))
    response = self.client.patch(url, format='json', data=data)
    self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
    self.assertIn(
        'Cannot change ethernet when exposing in DHCP',
        response.data['__all__']
    )