Function min_max

tests/test_rb_tree2.rs:98–105

()

#[test]
fn min_max() {
    let mut tree = Tree::default();
    for v in 0..10 {
        tree.insert(v, v);
    }
    assert_eq!(tree.min(), Some(&0));
    assert_eq!(tree.max(), Some(&9));
}

#[test]
fn keys() {