[Cpoll]

You forgot 0, -1, null, "1".

[bluGill]

Since I work in a strongly typed languages the last two will fail to compile and are thus not worth the bother - those who don't have that luxury of course need to test the edge cases that apply to them. The first are maybe, in my experience they are rarely a problem, but we need to go from the abstract to the particular algorithm before we can have a discussion on if they are potentially a problem or not.

[OptionOfT]

If you're using Rust you can push it one level further: use a NonZeroU*.

More than that and you'll need nightly for now: https://docs.rs/ranged_integers/latest/ranged_integers/