Smallest number with all set bits

#[test]
fn test_1() {
    let start = std::time::Instant::now();
    let val = Solution::smallest_number(5);
    let expected = 7;
    log_result!(val == expected, "test_1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_2() {
    let start = std::time::Instant::now();
    let val = Solution::smallest_number(10);
    let expected = 15;
    log_result!(val == expected, "test_2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_3() {
    let start = std::time::Instant::now();
    let val = Solution::smallest_number(3);
    let expected = 3;
    log_result!(val == expected, "test_3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_4() {
    let start = std::time::Instant::now();
    let val = Solution::smallest_number(1);
    let expected = 1;
    log_result!(val == expected, "test_4", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_5() {
    let start = std::time::Instant::now();
    let val = Solution::smallest_number(1000);
    let expected = 1023;
    log_result!(val == expected, "test_5", start, &expected, &val);
    assert_eq!(val, expected);
}