% Attributes
There is a new edition of the book and this is an old link.
> Any item declaration may have an attribute applied to it.
```rust
// A function marked as a unit test
#[test]
fn test_foo() {
/* ... */
}
```
---
Here are the relevant sections in the new and old books:
* **[In the Rust Reference: Ch 6.5 — Attributes][2]**
* [In the first edition: Ch 3.27 — Attributes][1]
[1]: https://doc.rust-lang.org/1.30.0/book/first-edition/attributes.html
[2]: ../reference/attributes.html