Power of three

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

#[test]
fn test_power_of_three() {
    let start = std::time::Instant::now();
    let val = Solution::is_power_of_three(27);
    let expected = true;
    log_result!(val == expected, "test_power_of_three", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_zero() {
    let start = std::time::Instant::now();
    let val = Solution::is_power_of_three(0);
    let expected = false;
    log_result!(val == expected, "test_zero", start, &expected, &val);
    assert_eq!(val, expected);
}