def test_tuple_list():
coef_tuple = (1, -6, 11, -6)
coef_list = [1, -6, 11, -6]
cubic_tuple = Cubic(coef_tuple)
cubic_list = Cubic(coef_list)
assert cubic_tuple.roots() == cubic_list.roots()
def test_list_ndarray():
coef_list = [1, -6, 11, -6]
coef_ndarray = np.array(coef_list)
cubic_list = Cubic(coef_list)
cubic_ndarray = Cubic(coef_ndarray)
assert cubic_list.roots() == cubic_ndarray.roots()
def test_negative_roots():
cubic = Cubic([1, -4, -55, -50])
assert cubic.roots() == pytest.approx([-5, -1, 10], abs=ERROR_MAX)
def test_scaling_roots_invariance():
coef = np.array([1, -6, 11, -6])
cubic1 = Cubic(coef)
cubic2 = Cubic(2 * coef)
assert cubic1.roots() == cubic2.roots()
def test_scattered_roots():
cubic = Cubic([1, -103, 302, -200])
assert cubic.roots() == pytest.approx([1, 2, 100], abs=ERROR_MAX)
def test_distinct_roots():
cubic = Cubic([1, -6, 11, -6])
assert cubic.roots() == pytest.approx([1, 2, 3], abs=ERROR_MAX)
def test_triple_root():
cubic = Cubic([1, -3, 3, -1])
assert cubic.roots() == pytest.approx([1, 1, 1], abs=ERROR_MAX)
def test_double_root():
cubic = Cubic([1, -5, 8, -4])
assert cubic.roots() == pytest.approx([1, 2, 2], abs=ERROR_MAX)
def test_single_root():
cubic = Cubic([1, 1, 1, -3])
assert cubic.roots() == pytest.approx([1], abs=ERROR_MAX)