Doc test
- Rust course
- Intermediate
- Lesson 86/115
- 4 min
Write doc tests with ///.
Doc tests
Code blocks in doc comments written with /// are run by cargo test. This way the examples in the docs never go stale:
/// Metni büyük harfe çevirir.
///
/// ```
/// assert_eq!(metin::buyuk_harf("rust"), "RUST");
/// ```
pub fn buyuk_harf(s: &str) -> String {
s.to_uppercase()
}cargo doc --open generates HTML docs from the same comments. Blocks meant only for display are marked with ```ignore or ```no_run.
Doc comment sections
Conventional headings guide the reader:
/// İki sayıyı böler.
///
/// # Örnekler
/// ```
/// assert_eq!(bol(10, 2), Some(5));
/// ```
///
/// # Hatalar
/// `b` sıfırsa `None` döner.
pub fn bol(a: i32, b: i32) -> Option<i32> { .. }//! documents the module or crate it's inside; it's usually written at the top of lib.rs.
Practice Documented function
Inside mod metin, write pub fn buyuk_harf(s: &str) -> String with an example in a ``` code block in a /// doc comment. In main, print the result of metin::buyuk_harf("rust").
Starter code
fn main() {
// buraya yaz
}Sample solution
mod metin {
/// Metni büyük harfe çevirir.
///
/// ```
/// assert_eq!(metin::buyuk_harf("rust"), "RUST");
/// ```
pub fn buyuk_harf(s: &str) -> String {
s.to_uppercase()
}
}
fn main() {
println!("{}", metin::buyuk_harf("rust"));
}Expected output
RUST
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 For which crates do doc tests run?
- All files
- None, they're run by hand
- Library crates Correct answer
- Only binary crates
Explanation: Doc tests are compiled as separate small programs using the library from outside.
2 Doc comment
____ Metni büyük harfe çevirir.
pub fn buyuk_harf(s: &str) -> String {
s.to_uppercase()
}/// Metni büyük harfe çevirir.
pub fn buyuk_harf(s: &str) -> String {
s.to_uppercase()
}Explanation: /// documents the next item, and its code blocks are tested.
3 Syntax and meaning
| Term | Meaning |
|---|---|
/// |
Item doc |
//! |
Module doc |
```ignore |
Not run |
cargo doc |
Generates HTML docs |