Remove vowels from a string

#[test]
fn test_example1() {
    let start = std::time::Instant::now();
    let val = Solution::remove_vowels("leetcodeisacommunityforcoders".to_string());
    let expected = "ltcdscmmntyfrcdrs".to_string();
    log_result!(val == expected, "test_example1", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_example2() {
    let start = std::time::Instant::now();
    let val = Solution::remove_vowels("aeiou".to_string());
    let expected = "".to_string();
    log_result!(val == expected, "test_example2", start, &expected, &val);
    assert_eq!(val, expected);
}

#[test]
fn test_mixed() {
    let start = std::time::Instant::now();
    let val = Solution::remove_vowels("hello".to_string());
    let expected = "hll".to_string();
    log_result!(val == expected, "test_mixed", start, &expected, &val);
    assert_eq!(val, expected);
}

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

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