% Testing

<small>There is a new edition of the book and this is an old link.</small>

> Rust includes support for writing software tests within the language itself.

```rust
#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {
    }
}
```

---

Here are the relevant sections in the new and old books:

* **[in the current edition: Ch 11.00 — Testing][2]**
* <small>[In the first edition: Ch 4.2 — Testing][1]</small>


[1]: https://doc.rust-lang.org/1.30.0/book/first-edition/testing.html
[2]: ch11-00-testing.html