trait Speak {
    String speak(self*);
}

struct Dog {
    String name,
}

impl Speak for Dog {
    String speak(self*) {
        "woof"
    }
}

pub void test_trait_impl() {
    let d = Dog { name: "Rex" };
    assert_eq!(d.speak(), "woof");
}

trait Greet : Speak {
    String greet(self*);
}

impl Greet for Dog {
    String greet(self*) {
        "hello"
    }
}

pub void test_trait_with_requirement() {
    let d = Dog { name: "Buddy" };
    assert_eq!(d.speak(), "woof");
    assert_eq!(d.greet(), "hello");
}

pub void run_tests() {
    test_trait_impl();
    test_trait_with_requirement();
}