Maximum value of a string in an array

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_value(vec!["alic3".to_string(), "bob".to_string(), "3".to_string(), "4".to_string(), "00000".to_string()]);
    let expected = 5;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_value(vec!["1".to_string(), "01".to_string(), "001".to_string(), "0001".to_string()]);
    let expected = 1;
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t3() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_value(vec!["abc".to_string()]);
    let expected = 3;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_value(vec!["99".to_string()]);
    let expected = 99;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::maximum_value(vec!["a".to_string(), "99".to_string(), "abc4".to_string()]);
    let expected = 99;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}