Other Types of Tests

Integration Tests

If you want to test your library as a client, use an integration test.

Create a .rs file under tests/:

// tests/my_library.rs
use my_library::init;

fn test_init() {

These tests only have access to the public API of your crate.

Documentation Tests

Rust has built-in support for documentation tests:

fn main() {
/// Shortens a string to the given length.
/// ```
/// # use playground::shorten_string;
/// assert_eq!(shorten_string("Hello World", 5), "Hello");
/// assert_eq!(shorten_string("Hello World", 20), "Hello World");
/// ```
pub fn shorten_string(s: &str, length: usize) -> &str {
    &s[..std::cmp::min(length, s.len())]
  • Code blocks in /// comments are automatically seen as Rust code.
  • The code will be compiled and executed as part of cargo test.
  • Adding # in the code will hide it from the docs, but will still compile/run it.
  • Test the above code on the Rust Playground.