def test_alt_updates(self, disc_lr, gen_lr):
    learning_rates = gan.GANTuple(disc=disc_lr, gen=gen_lr)
    num_updates = gan.GANTuple(disc=1, gen=1)
    drift_coeffs = drift_utils.get_dd_coeffs(
        drift_utils.PlayerOrder.disc_first, False, learning_rates,
        num_updates=num_updates)

    self.assertEqual(drift_coeffs.disc.self_norm, 0.5 * disc_lr)
    self.assertEqual(drift_coeffs.disc.other_norm, 0.0)
    self.assertEqual(drift_coeffs.disc.other_dot_prod, 0.5 * disc_lr)

    self.assertEqual(drift_coeffs.gen.self_norm, 0.5 * gen_lr)
    self.assertEqual(drift_coeffs.gen.other_norm, 0.0)
    self.assertEqual(
        drift_coeffs.gen.other_dot_prod,
        0.5 * gen_lr * (1 - 2 * disc_lr / gen_lr))