def test_func(self):
f = lambda x: x * x
assert approx(limit(f, 0), 0, abs=10 ** -10)
assert 4 == approx(limit(f, 2))
assert 4 == approx(limit(f, -2))
def test_vertical_asymptote_has_neg_limit(self):
f = lambda x: -1 / (x * x)
assert limit(f, 0) < 0
def test_vertical_asymptote_no_limit(self):
f = lambda x: ((x + 3) * (x - 2)) / ((x + 3) * (x + 2))
assert limit(f, -2) is None
def test_vertical_asymptote_has_limit(self):
f = lambda x: 1 / (x * x)
assert isinf(limit(f, 0))
assert limit(f, 0) > 0
def test_hole(self):
f = lambda x: ((x + 3) * (x - 2)) / ((x + 3) * (x + 2))
assert 5 == approx(limit(f, -3))