Find closest number to zero

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::find_closest_number(vec![-4, -2, 1, 4, 8]);
    let expected = 1;
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::find_closest_number(vec![2, -1, 1]);
    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::find_closest_number(vec![0]);
    let expected = 0;
    log_result!(val == expected, "t3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::find_closest_number(vec![-5, 5]);
    let expected = 5;
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::find_closest_number(vec![-3, -3, 3]);
    let expected = 3;
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}