From 05fbbdfe81c37fc7b8f5e619754b7ef6ccf06b23 Mon Sep 17 00:00:00 2001
From: David Rusu <davidrusu.me@gmail.com>
Date: Sun, 21 Jul 2024 19:59:10 +0400
Subject: [PATCH] cl: make transfer scenario readable

---
 goas/cl/ledger/tests/simple_transfer.rs | 50 +++++++++++++++++--------
 goas/cl/proof_statements/src/lib.rs     |  1 -
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/goas/cl/ledger/tests/simple_transfer.rs b/goas/cl/ledger/tests/simple_transfer.rs
index 6bb8def..66fad90 100644
--- a/goas/cl/ledger/tests/simple_transfer.rs
+++ b/goas/cl/ledger/tests/simple_transfer.rs
@@ -1,6 +1,22 @@
 use ledger::{bundle::ProvedBundle, partial_tx::ProvedPartialTx};
 use rand_core::CryptoRngCore;
 
+struct User(cl::NullifierSecret);
+
+impl User {
+    fn random(mut rng: impl CryptoRngCore) -> Self {
+        Self(cl::NullifierSecret::random(&mut rng))
+    }
+
+    fn pk(&self) -> cl::NullifierCommitment {
+        self.0.commit()
+    }
+
+    fn sk(&self) -> cl::NullifierSecret {
+        self.0
+    }
+}
+
 fn receive_utxo(
     note: cl::NoteWitness,
     nf_pk: cl::NullifierCommitment,
@@ -13,37 +29,39 @@ fn receive_utxo(
 fn test_simple_transfer() {
     let mut rng = rand::thread_rng();
 
-    let sender_nf_sk = cl::NullifierSecret::random(&mut rng);
-    let sender_nf_pk = sender_nf_sk.commit();
+    // alice is sending 8 NMO to bob.
 
-    let recipient_nf_pk = cl::NullifierSecret::random(&mut rng).commit();
+    let alice = User::random(&mut rng);
+    let bob = User::random(&mut rng);
 
-    // Assume the sender has received an unspent output from somewhere
-    let utxo = receive_utxo(cl::NoteWitness::basic(10, "NMO"), sender_nf_pk, &mut rng);
+    // Alice has an unspent note worth 10 NMO
+    let utxo = receive_utxo(cl::NoteWitness::basic(10, "NMO"), alice.pk(), &mut rng);
+    let alices_input = cl::InputWitness::random(utxo, alice.sk(), &mut rng);
 
-    let note_commitments = vec![utxo.commit_note()];
+    // Alice wants to send 8 NMO to bob
+    let bobs_output =
+        cl::OutputWitness::random(cl::NoteWitness::basic(8, "NMO"), bob.pk(), &mut rng);
 
-    let input = cl::InputWitness::random(utxo, sender_nf_sk, &mut rng);
-
-    // and wants to send 8 NMO to some recipient and return 2 NMO to itself.
-    let recipient_output =
-        cl::OutputWitness::random(cl::NoteWitness::basic(8, "NMO"), recipient_nf_pk, &mut rng);
+    // .. and return the 2 NMO in change to herself.
     let change_output =
-        cl::OutputWitness::random(cl::NoteWitness::basic(2, "NMO"), sender_nf_pk, &mut rng);
+        cl::OutputWitness::random(cl::NoteWitness::basic(2, "NMO"), alice.pk(), &mut rng);
 
+    // Construct the ptx consuming Alices inputs and producing the two outputs.
     let ptx_witness = cl::PartialTxWitness {
-        inputs: vec![input],
-        outputs: vec![recipient_output, change_output],
+        inputs: vec![alices_input],
+        outputs: vec![bobs_output, change_output],
     };
 
+    // assume we only have one note commitment on chain for now ...
+    let note_commitments = vec![utxo.commit_note()];
     let proved_ptx = ProvedPartialTx::prove(&ptx_witness, &note_commitments);
 
-    assert!(proved_ptx.verify());
+    assert!(proved_ptx.verify()); // It's a valid ptx.
 
     let bundle = cl::Bundle {
         partials: vec![ptx_witness.commit()],
     };
 
     let proved_bundle = ProvedBundle::prove(&bundle, &ptx_witness.balance_blinding());
-    assert!(proved_bundle.verify());
+    assert!(proved_bundle.verify()); // The bundle is balanced.
 }
diff --git a/goas/cl/proof_statements/src/lib.rs b/goas/cl/proof_statements/src/lib.rs
index 36287af..8e58650 100644
--- a/goas/cl/proof_statements/src/lib.rs
+++ b/goas/cl/proof_statements/src/lib.rs
@@ -1,4 +1,3 @@
 pub mod death_constraint;
 pub mod input;
-pub mod partial_tx;
 pub mod ptx;