def test_ref_get_with_invalid_election_id_non_existent_election_id(self):
        response = self.client.get(
            reverse('results-export'),
            { 'election': '69' },
            HTTP_REFERER=reverse('results'),
            follow=True
        )

        messages = list(response.context['messages'])
        self.assertEqual(
            messages[0].message,
            'You specified an ID for a non-existent election.'
        )
        self.assertRedirects(response, reverse('results'))
def test_hyperfocal_distance():
    f, N, c = symbols('f, N, c')
    assert hyperfocal_distance(f=f, N=N, c=c) == f**2/(N*c)
    assert ae(hyperfocal_distance(f=0.5, N=8, c=0.0033), 9.47, 2)