From 330d79379f9a4d4d74b399e3b23200b0fbeb6f1d Mon Sep 17 00:00:00 2001
From: Sergio Chouhy <sergio.chouhy@gmail.com>
Date: Mon, 18 Aug 2025 14:55:50 -0300
Subject: [PATCH] add message serialization roundtrip test

---
 nssa/core/src/lib.rs                          |  7 ++--
 .../encoding.rs                               | 11 +++---
 .../privacy_preserving_transaction/message.rs | 38 ++++++++++++++-----
 3 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/nssa/core/src/lib.rs b/nssa/core/src/lib.rs
index c0f8d58..a247d19 100644
--- a/nssa/core/src/lib.rs
+++ b/nssa/core/src/lib.rs
@@ -47,7 +47,7 @@ impl Tag {
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
-pub struct EncryptedAccountData;
+pub struct EncryptedAccountData(u8);
 
 impl EncryptedAccountData {
     pub fn new(
@@ -57,12 +57,13 @@ impl EncryptedAccountData {
         Ivk: &IncomingViewingPublicKey,
     ) -> Self {
         // TODO: implement
-        Self
+        Self(0)
     }
 
     #[cfg(feature = "host")]
     pub fn from_cursor(cursor: &mut Cursor<&[u8]>) -> Result<Self, NssaCoreError> {
-        todo!()
+        let dummy_value = EncryptedAccountData(0);
+        Ok(dummy_value)
     }
 }
 
diff --git a/nssa/src/privacy_preserving_transaction/encoding.rs b/nssa/src/privacy_preserving_transaction/encoding.rs
index 2a19ebe..78cb47c 100644
--- a/nssa/src/privacy_preserving_transaction/encoding.rs
+++ b/nssa/src/privacy_preserving_transaction/encoding.rs
@@ -39,18 +39,21 @@ impl Message {
         // Encrypted post states
         let encrypted_accounts_post_states_len: u32 =
             self.encrypted_private_post_states.len() as u32;
+        bytes.extend_from_slice(&encrypted_accounts_post_states_len.to_le_bytes());
         for encrypted_account in &self.encrypted_private_post_states {
             bytes.extend_from_slice(&encrypted_account.to_bytes());
         }
 
         // New commitments
         let new_commitments_len: u32 = self.new_commitments.len() as u32;
+        bytes.extend_from_slice(&new_commitments_len.to_le_bytes());
         for commitment in &self.new_commitments {
             bytes.extend_from_slice(&commitment.to_byte_array());
         }
 
         // New nullifiers
         let new_nullifiers_len: u32 = self.new_nullifiers.len() as u32;
+        bytes.extend_from_slice(&new_nullifiers_len.to_le_bytes());
         for nullifier in &self.new_nullifiers {
             bytes.extend_from_slice(&nullifier.to_byte_array());
         }
@@ -58,11 +61,6 @@ impl Message {
     }
 
     pub(crate) fn from_cursor(cursor: &mut Cursor<&[u8]>) -> Result<Self, NssaError> {
-        let prefix = {
-            let mut this = [0u8; MESSAGE_ENCODING_PREFIX_LEN];
-            cursor.read_exact(&mut this)?;
-            this
-        };
         let prefix = {
             let mut this = [0u8; MESSAGE_ENCODING_PREFIX_LEN];
             cursor.read_exact(&mut this)?;
@@ -138,3 +136,6 @@ impl Message {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {}
diff --git a/nssa/src/privacy_preserving_transaction/message.rs b/nssa/src/privacy_preserving_transaction/message.rs
index f6e5e65..5250e07 100644
--- a/nssa/src/privacy_preserving_transaction/message.rs
+++ b/nssa/src/privacy_preserving_transaction/message.rs
@@ -37,14 +37,15 @@ impl Message {
 
 #[cfg(test)]
 pub mod tests {
+    use std::io::Cursor;
+
     use nssa_core::account::{
         Account, Commitment, Nullifier, NullifierPublicKey, NullifierSecretKey,
     };
 
     use crate::{Address, privacy_preserving_transaction::message::Message};
 
-    #[test]
-    fn test_constructor() {
+    fn message_for_tests() -> Message {
         let account1 = Account::default();
         let account2 = Account::default();
 
@@ -67,24 +68,41 @@ pub mod tests {
         let old_commitment = Commitment::new(&Npk1, &account1);
         let new_nullifiers = vec![Nullifier::new(&old_commitment, &nsk1)];
 
-        let expected_message = Message {
+        Message {
             public_addresses: public_addresses.clone(),
             nonces: nonces.clone(),
             public_post_states: public_post_states.clone(),
             encrypted_private_post_states: encrypted_private_post_states.clone(),
             new_commitments: new_commitments.clone(),
             new_nullifiers: new_nullifiers.clone(),
-        };
+        }
+    }
+
+    #[test]
+    fn test_constructor() {
+        let message = message_for_tests();
+        let expected_message = message.clone();
 
         let message = Message::new(
-            public_addresses,
-            nonces,
-            public_post_states,
-            encrypted_private_post_states,
-            new_commitments,
-            new_nullifiers,
+            message.public_addresses,
+            message.nonces,
+            message.public_post_states,
+            message.encrypted_private_post_states,
+            message.new_commitments,
+            message.new_nullifiers,
         );
 
         assert_eq!(message, expected_message);
     }
+
+    #[test]
+    fn test_message_serialization_roundtrip() {
+        let message = message_for_tests();
+
+        let bytes = message.to_bytes();
+        let mut cursor = Cursor::new(bytes.as_ref());
+        let message_from_cursor = Message::from_cursor(&mut cursor).unwrap();
+
+        assert_eq!(message, message_from_cursor);
+    }
 }