def test_necessario(self):
        self.assertTrue(self.seg_p)

        seg_p2 = itau.registros.SegmentoP()
        self.assertFalse(seg_p2.necessario())

        seg_p2.controle_banco = 33
        self.assertFalse(seg_p2.necessario())

        seg_p2.vencimento_titulo = 10102012
        self.assertTrue(seg_p2.necessario())
def test_lens_makers_formula():
    n1, n2 = symbols('n1, n2')
    m1 = Medium('m1', permittivity=e0, n=1)
    m2 = Medium('m2', permittivity=e0, n=1.33)
    assert lens_makers_formula(n1, n2, 10, -10) == 5*n2/(n1 - n2)
    assert ae(lens_makers_formula(m1, m2, 10, -10), -20.15, 2)
    assert ae(lens_makers_formula(1.33, 1, 10, -10),  15.15, 2)