Function change_case::upper_case

pub fn upper_case(input: &str) -> String

Change to upper case

use change_case::upper_case;
assert_eq!(upper_case(""), "");
assert_eq!(upper_case("test"), "TEST");
assert_eq!(upper_case("test string"), "TEST STRING");
assert_eq!(upper_case("Test String"), "TEST STRING");
assert_eq!(upper_case("\u{0131}"), "I");