def test_causal1(self): a = Circuit() a.add('V1 1 0 {4 + 2 * u(t)}; down') a.add('R1 1 2 2; right=2') a.add('L1 2 3 2; down') a.add('W 0 3; right') self.assertEqual(a.sub['s'].is_causal, True, "Causal incorrect") self.assertEqual2(a.L1.v, 2 * exp(-t) * u(t), "L current incorrect")