def test_increment_integer(self):
# test the increment integer function
key = Fernet.generate_key()
fernet = Fernet(key)
# test normal behavior
for i in range(100):
assert fernet._increment_integer(i) == i + 1
# test edge case
i = 2**128-1
assert fernet._increment_integer(i) == 0
# test big integer
with pytest.raises(AssertionError) as e:
fernet._increment_integer(2**128)
# test negative integer
with pytest.raises(AssertionError) as e:
fernet._increment_integer(-1)
