Abstracted message serialisation test code.

When implementing tests for signing and/or encrypting messages, we can just implement the `MessageSender`/`MessageReceiver` traits when needed then call into this function.

(Those traits may need refactoring if the format of the adapter is not desireable (i.e. `&self` instead of `&mut self` or `self`; we could only blanket-impl those function to `Fn()` closures, not `FnMut()` or `FnOnce()`. (not that we should try this.)), but for now we"ll leave it as it is.)

Fortune for rsh's current commit: Small blessing − 小吉

src/message.rs

@@ -373,23 +373,36 @@ impl<V: ?Sized + MessageValue> SerializedMessage<V>
 mod tests
 {
     use super::*;
-    #[test]
-    fn message_serial()
+
+    /// Generic message test function
+    fn message_serial_generic<S,D>(s: S, d: D)
+    where S: MessageSender,
+	  D: MessageReceiver
     {
+	eprintln!("=== Message serialisation with tc, rc: S: {}, D: {}", std::any::type_name::<S>(), std::any::type_name::<D>());
 	let message = MessageBuilder::new()
 	    .create(format!("This is a string, and some random data: {:?}", aes::AesKey::generate().unwrap()))
 	    .expect("Failed to create message");
 	println!(">> Created message: {:?}", message);
-	let serialised = message.serialise(()).expect("Failed to serialise message");
+	let serialised = message.serialise(s).expect("Failed to serialise message");
 	println!(">> Serialised message: {:?}", serialised);
 	let binary = serialised.into_bytes();
 	println!(">> Written to {} bytes", binary.len());
 	let read = SerializedMessage::from_bytes(&binary).expect("Failed to read serialised message from binary");
 	println!(">> Read from bytes: {:?}", read);
-	let deserialised = Message::deserialize(&read, ()).expect("Failed to deserialise message");
+	let deserialised = Message::deserialize(&read, d).expect("Failed to deserialise message");
 	println!(">> Deserialised message: {:?}", deserialised);
 	
 	assert_eq!(message, deserialised, "Messages not identical");
 	assert_eq!(message.into_value(), deserialised.into_value(), "Message values not identical");
+	eprintln!("=== Passed (S: {}, D: {}) ===", std::any::type_name::<S>(), std::any::type_name::<D>());
     }
+    
+    #[test]
+    fn message_serial_basic()
+    {
+	message_serial_generic((), ());
+    }
+
+    //TODO: message_serial_sign(), message_serial_encrypted(), message_serial_encrypted_sign()
 }