Rust Daily Learning - Day 17

• Testing
• Documentation

In this session, we’ll learn about testing and documentation in Rust. Rust has built-in support for both testing and documentation, making it easy to create quality code.

Testing

Rust’s testing framework is integrated into the language and the cargo tool. There are two types of tests in Rust: unit tests and integration tests.

Unit Tests

Unit tests are small, focused tests that check the functionality of a single module, function, or method. They are usually located in the same file as the code they test, inside a #[cfg(test)] module.

fn add(a: i32, b: i32) -> i32 {
    a + b
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_add() {
        assert_eq!(add(1, 2), 3);
    }
}

Integration Tests

Integration tests are located in the tests directory at the top level of your project. They test the interaction between multiple components of your application.

To create an integration test, create a new file in the tests directory:

$ touch tests/integration_test.rs

Then write the test:

use my_crate::add;

#[test]
fn test_add() {
    assert_eq!(add(1, 2), 3);
}

Run the tests using cargo test.

Documentation

Rust has built-in support for generating documentation using the rustdoc tool. You can write documentation comments with triple slashes /// and use Markdown for formatting.

/// Adds two numbers together.
///
/// # Examples
///
/// ```
/// use my_crate::add;
///
/// assert_eq!(add(1, 2), 3);
/// ```
pub fn add(a: i32, b: i32) -> i32 {
    a + b
}

Generate the documentation using cargo doc. It will create HTML documentation in the target/doc directory. Open the generated index.html file in your browser to view the documentation.

Keep practicing testing and documentation to ensure your Rust code is of high quality and well-documented!