Length of last word

#[test]
fn test_example_1() {
    let start = std::time::Instant::now();
    let val = Solution::length_of_last_word("Hello World".to_string());
    let expected = 5;
    log_result!(val == expected, "test_example_1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_multiple_words() {
    let start = std::time::Instant::now();
    let val = Solution::length_of_last_word("luffy is still joyboy".to_string());
    let expected = 6;
    log_result!(val == expected, "test_multiple_words", start, &expected, &val);
    assert_eq!(val, expected);
}

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

#[test]
fn test_trailing_spaces() {
    let start = std::time::Instant::now();
    let val = Solution::length_of_last_word("   fly me   to   the moon  ".to_string());
    let expected = 4;
    log_result!(val == expected, "test_trailing_spaces", start, &expected, &val);
    assert_eq!(val, expected);
}