Minimum element after replacement with digit sum

#[test]
fn test_all_single_digit() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![5, 7, 9]);
    let expected = 5;
    log_result!(val == expected, "test_all_single_digit", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example1() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![10, 12, 13, 14]);
    let expected = 1;
    log_result!(val == expected, "test_example1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example2() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![1, 2, 3, 4]);
    let expected = 1;
    log_result!(val == expected, "test_example2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example3() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![999, 19, 199]);
    let expected = 10;
    log_result!(val == expected, "test_example3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_mixed() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![100, 99, 11]);
    let expected = 1;
    log_result!(val == expected, "test_mixed", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_single_element() {
    let start = std::time::Instant::now();
    let val = Solution::min_element(vec![9999]);
    let expected = 36;
    log_result!(val == expected, "test_single_element", start, &expected, &val);
    assert_eq!(val, expected);
}