> add assertions to your code.

Yes, and many programming languages have assertions such as "assert greater than or equal to".

For example with Rust and the Assertables crate:

    fn calculate_something() -> f64 {
        let big = get_big_number();
        let small = get_small_number();
        assert_ge!(big, small); // >= or panic with message
        (big - small).sqrt
    }

It turns out it's even better if your code has good error handling, such as a runtime assert macro that can return a result that is NaN (not a number) or a "maybe" result that is either Ok or Err.

For example with Rust and the Assertables crate:

    fn calculate_something() -> Result(f64, String) {
        let big = get_big_number()
        let small = get_small_number()
        assert_ge!(big, small)?; // >= or return Err(message)
        (big - small).sqrt
    }