Find three consecutive integers that sum to a given number

#[test]
fn t1() {
    let start = std::time::Instant::now();
    let val = Solution::sum_of_three(33);
    let expected = vec![10, 11, 12];
    log_result!(val == expected, "t1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t2() {
    let start = std::time::Instant::now();
    let val = Solution::sum_of_three(4);
    let expected = (vec![] as Vec<i64>);
    log_result!(val == expected, "t2", start, &expected, &val);
    assert_eq!(val, expected);
}

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

#[test]
fn t4() {
    let start = std::time::Instant::now();
    let val = Solution::sum_of_three(3);
    let expected = vec![0, 1, 2];
    log_result!(val == expected, "t4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn t5() {
    let start = std::time::Instant::now();
    let val = Solution::sum_of_three(6);
    let expected = vec![1, 2, 3];
    log_result!(val == expected, "t5", start, &expected, &val);
    assert_eq!(val, expected);
}