Function test

src/encode/value_ref.rs:153–157

(err: E)

        let err = Error(WriteError(io::Error::new(io::ErrorKind::Other, "unexpected EOF")));

        fn test<E: error::Error>(err: E) {
            assert_eq!("error while writing MessagePack'ed value", err.description());
            assert!(err.cause().is_some());
            assert_eq!("unexpected EOF", err.cause().unwrap().description());
        }

        test(err);
    }