Added unit test to test that new cloning feature works as intended

        assert_eq!(hex::encode(hasher.finish()), expected);

    }

    #[test]

    fn cloning_allows_incremental_hashing() {

        let expected = "a9993e364706816aba3e25717850c26c9cd0d89d";

        let mut hasher = Sha1::new();

        hasher.update(b"a");

        let mut incr_hasher = hasher.clone();

        incr_hasher.update(b"bc");

        assert_eq!(hex::encode(incr_hasher.finish()), expected);

        assert_ne!(hex::encode(hasher.finish()), expected);

    }

    #[test]

    fn standalone_224() {

        let data = b"abc";