let digests = create_digests(&[alg], Box::new(reader)).unwrap();
assert_eq!(digests.len(), 1);
assert_eq!(digests[0], (alg, hex::decode(hash).unwrap()));
let digests = create_digests(&[alg], Box::new(reader)).unwrap();
assert_eq!(digests.len(), 1);
assert_eq!(digests[0], (alg, hex::decode(hash).unwrap()));