Comment by skolemtotem

Rust takes a similar approach. For unit tests, you use the #[cfg(test)] attribute (/ pragma / directive) for conditional compilation, and #[test] to mark a function that is a unit test, which is run whenever you run the `cargo test` command. Also, any Rust code in Markdown fences in documentation is, by default, also run by `cargo test`, which you can disable for an individual code block by marking it as `rust,norun` instead of `rust`.