def test_setitem_raises_error(self):
"""Test that setitem raises error on invalid inputs."""
lb = LinearBinomial(5, 1)
qt = QuadraticTrinomial(1, 2, 3)
self.assertRaises(DegreeError, lb.__setattr__, "a", 0)
self.assertRaises(DegreeError, qt.__setattr__, "a", 0)
lb = LinearBinomial(5, 1)
qt = QuadraticTrinomial(1, 2, 3)
self.assertRaises(DegreeError, lb.__setitem__, 1, 0)
self.assertRaises(DegreeError, qt.__setitem__, 2, 0)
def test_trinomial_binomial_addition(self):
"""Test that QuadraticTrinomial behaves as expected."""
a = QuadraticTrinomial(1, 2, 3)
b = LinearBinomial(1, 2)
e = QuadraticTrinomial(1, 3, 5)
ep = Polynomial(e)
# a + b is safe because a's degree does not change.
self._assert_polynomials_are_the_same(e, a + b)
# b + a requires a cast since b's degree does change.
self._assert_polynomials_are_the_same(ep, b + a)
def test_quadratic_trinomial_default_init(self):
"""Test that the default quadratic trinomial is 'x^2 + x + 1'."""
expected = Polynomial(1, 1, 1)
qt = QuadraticTrinomial()
self.assertEqual(expected, qt)
def test_quadratic_trinomial(self):
"""Test that repr() output of a QuadraticTrinomial is valid."""
expect = "QuadraticTrinomial(1, -4, 4)"
r = repr(QuadraticTrinomial(1, -4, 4))
self.assertEqual(expect, r)
def test_quadratic_trinomial_init(self):
"""Test that a quadratic trinomial is successfully initialized."""
a, b, c = 2, 3, 4
expected = Polynomial(a, b, c)
qt = QuadraticTrinomial(a, b, c)
self.assertEqual(expected, qt)
def test_pow_by_non_integer(self):
"""Test that pow by non-integer type is not possible."""
to_test = [
Polynomial(1, 2, 3),
Monomial(1, 2),
Constant(5),
ZeroPolynomial(),
QuadraticTrinomial(1, 3, 7),
LinearBinomial(9, 2),
]
for val in to_test:
self.assertRaises(ValueError, val.__pow__, 1.2)
self.assertRaises(ValueError, val.__ipow__, 1.5)
def test_pos(self):
"""Test that a Polynomial is equal to its positive version."""
a = Polynomial(1, 2, 3)
b = Monomial(1, 2)
c = Constant(5)
d = ZeroPolynomial()
e = QuadraticTrinomial(1, 3, 7)
f = LinearBinomial(9, 2)
self._assert_polynomials_are_the_same(a, +a)
self._assert_polynomials_are_the_same(b, +b)
self._assert_polynomials_are_the_same(c, +c)
self._assert_polynomials_are_the_same(d, +d)
self._assert_polynomials_are_the_same(e, +e)
self._assert_polynomials_are_the_same(f, +f)
def test_div_by_zero(self):
"""Test that division by 0 is not possible."""
to_test = [
Polynomial(1, 2, 3),
Monomial(1, 2),
Constant(5),
ZeroPolynomial(),
QuadraticTrinomial(1, 3, 7),
LinearBinomial(9, 2),
]
for val in to_test:
self.assertRaises(ZeroDivisionError, val.__floordiv__, 0)
self.assertRaises(ZeroDivisionError, val.__ifloordiv__, 0)
self.assertRaises(ZeroDivisionError, val.__mod__, 0)
self.assertRaises(ZeroDivisionError, val.__imod__, 0)
self.assertRaises(ZeroDivisionError, val.__divmod__, 0)
def test_inequality(self):
"""Test that distinct values do not equal other."""
to_test = [
Polynomial(1, 2, 3),
Monomial(1, 2),
Constant(5),
ZeroPolynomial(),
QuadraticTrinomial(1, 3, 7),
LinearBinomial(9, 2), 7
]
for i, lhs in enumerate(to_test):
for j, rhs in enumerate(to_test):
if i == j:
self.assertTrue(lhs == lhs)
self.assertFalse(lhs != lhs)
else:
self.assertFalse(lhs == rhs)
self.assertNotEqual(lhs, rhs)
def test_zero_discriminant_roots(self):
"""Test the real and complex roots and factors for D == 0."""
qt = QuadraticTrinomial(1, 4, 4)
exp_discri = 0
exp_real_roots = (-2, -2)
exp_complex_roots = (-2, -2)
exp_real_factors = (1, LinearBinomial(1, 2), LinearBinomial(1, 2))
exp_complex_factors = exp_real_factors
res_discri = qt.discriminant
res_real_roots = qt.real_roots
res_complex_roots = qt.complex_roots
res_real_factors = qt.real_factors
res_complex_factors = qt.complex_factors
self.assertEqual(exp_discri, res_discri)
self.assertEqual(exp_real_roots, res_real_roots)
self.assertEqual(exp_complex_roots, res_complex_roots)
self.assertEqual(exp_real_factors, res_real_factors)
self.assertEqual(exp_complex_factors, res_complex_factors)
def test_positive_discriminant_roots(self):
"""Test the real and complex roots and factors for D > 0."""
qt = QuadraticTrinomial(1, -5, 6)
exp_discri = 1
exp_real_roots = (3, 2)
exp_complex_roots = (3, 2)
exp_real_factors = (1, LinearBinomial(1, -3), LinearBinomial(1, -2))
exp_complex_factors = exp_real_factors
res_discri = qt.discriminant
res_real_roots = qt.real_roots
res_complex_roots = qt.complex_roots
res_real_factors = qt.real_factors
res_complex_factors = qt.complex_factors
self.assertEqual(exp_discri, res_discri)
self.assertEqual(exp_real_roots, res_real_roots)
self.assertEqual(exp_complex_roots, res_complex_roots)
self.assertEqual(exp_real_factors, res_real_factors)
self.assertEqual(exp_complex_factors, res_complex_factors)
def test_setting_empty_terms_immutable_degree(self):
"""Test setting empty terms."""
immutable = [
QuadraticTrinomial(1, 2, 3),
LinearBinomial(1, 2),
]
for val in immutable:
self.assertRaises(DegreeError, val.__setattr__, "terms", [])
try:
a = Constant(0)
a.terms = []
a = Constant(5)
a.terms = []
except DegreeError:
self.assertFalse(True,
"Should be able to set Constant(0).terms to []")
a = Constant(1)
a.terms = []
def test_negative_discriminant_roots(self):
"""Test the real and complex roots and factors for D < 0."""
qt = QuadraticTrinomial(1, 2, 5)
exp_discri = -16
exp_real_roots = ()
exp_complex_roots = (-1 + 2j, -1 - 2j)
exp_real_factors = (qt, )
exp_complex_factors = (1, LinearBinomial(1, 1 - 2j),
LinearBinomial(1, 1 + 2j))
res_discri = qt.discriminant
res_real_roots = qt.real_roots
res_complex_roots = qt.complex_roots
res_real_factors = qt.real_factors
res_complex_factors = qt.complex_factors
self.assertEqual(exp_discri, res_discri)
self.assertEqual(exp_real_roots, res_real_roots)
self.assertEqual(exp_complex_roots, res_complex_roots)
self.assertEqual(exp_real_factors, res_real_factors)
self.assertEqual(exp_complex_factors, res_complex_factors)
def test_ipow_zero_gives_one(self):
"""Test that x **= 0 returns an appropriate 1 polynomial."""
to_test = [
Polynomial(1, 2, 3),
Monomial(1, 2),
Constant(5),
ZeroPolynomial(),
QuadraticTrinomial(1, 3, 7),
LinearBinomial(9, 2),
]
one_maps = {
Polynomial: Polynomial(1),
Monomial: Monomial(1, 0),
Constant: Constant(1),
ZeroPolynomial: Constant(1),
QuadraticTrinomial: Polynomial(1),
LinearBinomial: Polynomial(1),
}
for val in to_test:
expected = one_maps[type(val)]
val **= 0
self._assert_polynomials_are_the_same(expected, val)