Valid digit number

#[test]
fn ends_with_digit() {
    let start = std::time::Instant::now();
    let val = Solution::valid_digit(12345, 5);
    let expected = true;
    log_result!(val == expected, "ends_with_digit", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn example1() {
    let start = std::time::Instant::now();
    let val = Solution::valid_digit(101, 0);
    let expected = true;
    log_result!(val == expected, "example1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn example2() {
    let start = std::time::Instant::now();
    let val = Solution::valid_digit(232, 2);
    let expected = false;
    log_result!(val == expected, "example2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn example3() {
    let start = std::time::Instant::now();
    let val = Solution::valid_digit(5, 1);
    let expected = false;
    log_result!(val == expected, "example3", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn n_is_one_no_match() {
    let start = std::time::Instant::now();
    let val = Solution::valid_digit(1, 9);
    let expected = false;
    log_result!(val == expected, "n_is_one_no_match", start, &expected, &val);
    assert_eq!(val, expected);
}

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

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