Test a function in a crate

---

examples/testing/test-function/Cargo.toml

[package]
name = "test-function"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

examples/testing/test-function/src/main.rs

fn main() {
    println!("{}", add(2, 3));
}

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

#[test]
fn test_add() {
    assert_eq!(add(2, 3), 5);
}