wip: Provide enough funds to both parties

Also use cosntant backoff retry strategy as opposed to exponential
backoff. This is in case retrying several times quickly causes the
retry intervals to become large enough that the test is very slow
and/or the Bitcoin lock transaction expires.

The current problem occurs on the last message i.e. Bob sending
tx_redeem_encsig to Alice. The action is yielded for Bob to do it, but
Alice appears to never receive it (unconfirmed claim, requires more
logging).

swap/src/alice.rs

@@ -2,7 +2,7 @@
 //! Alice holds XMR and wishes receive BTC.
 use anyhow::Result;
 use async_trait::async_trait;
-use backoff::{future::FutureOperation as _, ExponentialBackoff};
+use backoff::{backoff::Constant as ConstantBackoff, future::FutureOperation as _};
 use genawaiter::GeneratorState;
 use libp2p::{
     core::{identity::Keypair, Multiaddr},
@@ -10,9 +10,9 @@ use libp2p::{
     NetworkBehaviour, PeerId,
 };
 use rand::rngs::OsRng;
-use std::sync::Arc;
+use std::{sync::Arc, time::Duration};
 use tokio::sync::Mutex;
-use tracing::{debug, info, warn};
+use tracing::{info, warn};
 use xmr_btc::alice;
 
 mod amounts;
@@ -55,6 +55,8 @@ pub async fn swap(
 
     impl Network {
         pub async fn send_message2(&mut self, proof: monero::TransferProof) {
+            tracing::debug!("Sending transfer proof");
+
             match self.channel.take() {
                 None => warn!("Channel not found, did you call this twice?"),
                 Some(channel) => {
@@ -67,6 +69,9 @@ pub async fn swap(
         }
     }
 
+    // TODO: For retry, use `backoff::ExponentialBackoff` in production as opposed
+    // to `ConstantBackoff`.
+
     #[async_trait]
     impl ReceiveBitcoinRedeemEncsig for Network {
         async fn receive_bitcoin_redeem_encsig(&mut self) -> xmr_btc::bitcoin::EncryptedSignature {
@@ -85,16 +90,13 @@ pub async fn swap(
 
                 Result::<_, backoff::Error<UnexpectedMessage>>::Ok(encsig)
             })
-            .retry(ExponentialBackoff {
+            .retry(ConstantBackoff::new(Duration::from_secs(1)))
-                max_elapsed_time: None,
-                ..Default::default()
-            })
             .await
             .expect("transient errors to be retried")
         }
     }
 
-    debug!("swapping ...");
+    tracing::debug!("swapping ...");
 
     let mut swarm = new_swarm(listen, local_port)?;
     let message0: bob::Message0;
@@ -107,7 +109,6 @@ pub async fn swap(
                 info!("Connection established with: {}", id);
             }
             OutEvent::Request(amounts::OutEvent::Btc { btc, channel }) => {
-                debug!("Got request from Bob to swap {}", btc);
                 let amounts = calculate_amounts(btc);
                 // TODO: We cache the last amounts returned, this needs improving along with
                 // verification of message 0.
@@ -138,7 +139,6 @@ pub async fn swap(
                 state0 = Some(state)
             }
             OutEvent::Message0(msg) => {
-                debug!("got message 0 from Bob");
                 // We don't want Bob to be able to crash us by sending an out of
                 // order message. Keep looping if Bob has not requested amounts.
                 if last_amounts.is_some() {

swap/src/bitcoin.rs

@@ -2,7 +2,7 @@ use std::time::Duration;
 
 use anyhow::Result;
 use async_trait::async_trait;
-use backoff::{future::FutureOperation as _, ExponentialBackoff};
+use backoff::{backoff::Constant as ConstantBackoff, future::FutureOperation as _};
 use bitcoin::{util::psbt::PartiallySignedTransaction, Address, Transaction};
 use bitcoin_harness::{bitcoind_rpc::PsbtBase64, Bitcoind};
 use reqwest::Url;
@@ -113,14 +113,14 @@ impl BroadcastSignedTransaction for Wallet {
     }
 }
 
+// TODO: For retry, use `backoff::ExponentialBackoff` in production as opposed
+// to `ConstantBackoff`.
+
 #[async_trait]
 impl WatchForRawTransaction for Wallet {
     async fn watch_for_raw_transaction(&self, txid: Txid) -> Transaction {
         (|| async { Ok(self.0.get_raw_transaction(txid).await?) })
-            .retry(ExponentialBackoff {
+            .retry(ConstantBackoff::new(Duration::from_secs(1)))
-                max_elapsed_time: None,
-                ..Default::default()
-            })
             .await
             .expect("transient errors to be retried")
     }
@@ -130,10 +130,7 @@ impl WatchForRawTransaction for Wallet {
 impl BlockHeight for Wallet {
     async fn block_height(&self) -> u32 {
         (|| async { Ok(self.0.block_height().await?) })
-            .retry(ExponentialBackoff {
+            .retry(ConstantBackoff::new(Duration::from_secs(1)))
-                max_elapsed_time: None,
-                ..Default::default()
-            })
             .await
             .expect("transient errors to be retried")
     }
@@ -160,10 +157,7 @@ impl TransactionBlockHeight for Wallet {
 
             Result::<_, backoff::Error<Error>>::Ok(block_height)
         })
-        .retry(ExponentialBackoff {
+        .retry(ConstantBackoff::new(Duration::from_secs(1)))
-            max_elapsed_time: None,
-            ..Default::default()
-        })
         .await
         .expect("transient errors to be retried")
     }

swap/src/bob.rs

@@ -2,7 +2,7 @@
 //! Bob holds BTC and wishes receive XMR.
 use anyhow::Result;
 use async_trait::async_trait;
-use backoff::{future::FutureOperation as _, ExponentialBackoff};
+use backoff::{backoff::Constant as ConstantBackoff, future::FutureOperation as _};
 use futures::{
     channel::mpsc::{Receiver, Sender},
     FutureExt, StreamExt,
@@ -10,7 +10,7 @@ use futures::{
 use genawaiter::GeneratorState;
 use libp2p::{core::identity::Keypair, Multiaddr, NetworkBehaviour, PeerId};
 use rand::rngs::OsRng;
-use std::{process, sync::Arc};
+use std::{process, sync::Arc, time::Duration};
 use tokio::sync::Mutex;
 use tracing::{debug, info, warn};
 
@@ -49,12 +49,17 @@ pub async fn swap(
 ) -> Result<()> {
     struct Network(Swarm);
 
+    // TODO: For retry, use `backoff::ExponentialBackoff` in production as opposed
+    // to `ConstantBackoff`.
+
     #[async_trait]
     impl ReceiveTransferProof for Network {
         async fn receive_transfer_proof(&mut self) -> monero::TransferProof {
             #[derive(Debug)]
             struct UnexpectedMessage;
 
+            tracing::debug!("Receiving transfer proof");
+
             let future = self.0.next().shared();
 
             (|| async {
@@ -68,10 +73,7 @@ pub async fn swap(
 
                 Result::<_, backoff::Error<UnexpectedMessage>>::Ok(proof)
             })
-            .retry(ExponentialBackoff {
+            .retry(ConstantBackoff::new(Duration::from_secs(1)))
-                max_elapsed_time: None,
-                ..Default::default()
-            })
             .await
             .expect("transient errors to be retried")
         }

swap/src/lib.rs

@@ -10,8 +10,6 @@ pub mod storage;
 #[cfg(feature = "tor")]
 pub mod tor;
 
-pub const ONE_BTC: u64 = 100_000_000;
-
 const REFUND_TIMELOCK: u32 = 10; // Relative timelock, this is number of blocks. TODO: What should it be?
 const PUNISH_TIMELOCK: u32 = 10; // FIXME: What should this be?
 

swap/src/monero.rs

@@ -75,6 +75,9 @@ impl CreateWalletForOutput for Wallet {
     }
 }
 
+// TODO: For retry, use `backoff::ExponentialBackoff` in production as opposed
+// to `ConstantBackoff`.
+
 #[async_trait]
 impl WatchForTransfer for Wallet {
     async fn watch_for_transfer(

swap/src/network/request_response.rs

@@ -6,6 +6,7 @@ use libp2p::{
 };
 use serde::{Deserialize, Serialize};
 use std::{fmt::Debug, io, marker::PhantomData};
+use tracing::debug;
 
 use crate::SwapAmounts;
 use xmr_btc::{alice, bob, monero};

swap/tests/e2e.rs

@@ -24,10 +24,12 @@ async fn swap() {
     let bitcoind = Bitcoind::new(&cli, "0.19.1").unwrap();
     let _ = bitcoind.init(5).await;
 
-    let btc = bitcoin::Amount::ONE_BTC;
+    let btc = bitcoin::Amount::from_sat(1_000_000);
-    let _btc_alice = bitcoin::Amount::ZERO;
+    let btc_alice = bitcoin::Amount::ZERO;
     let btc_bob = btc * 10;
 
+    // this xmr value matches the logic of alice::calculate_amounts i.e. btc *
+    // 10_000 * 100
     let xmr = 1_000_000_000_000;
     let xmr_alice = xmr * 10;
     let xmr_bob = 0;
@@ -54,8 +56,8 @@ async fn swap() {
     let bob_xmr_wallet = Arc::new(swap::monero::Wallet(monero.bob_wallet_rpc_client()));
 
     let alice_swap = alice::swap(
-        alice_btc_wallet,
+        alice_btc_wallet.clone(),
-        alice_xmr_wallet,
+        alice_xmr_wallet.clone(),
         alice_multiaddr.clone(),
         None,
     );
@@ -63,15 +65,33 @@ async fn swap() {
     let (cmd_tx, mut _cmd_rx) = mpsc::channel(1);
     let (mut rsp_tx, rsp_rx) = mpsc::channel(1);
     let bob_swap = bob::swap(
-        bob_btc_wallet,
+        bob_btc_wallet.clone(),
-        bob_xmr_wallet,
+        bob_xmr_wallet.clone(),
         btc.as_sat(),
         alice_multiaddr,
         cmd_tx,
         rsp_rx,
     );
 
+    // automate the verification step by accepting any amounts sent over by Alice
     rsp_tx.try_send(swap::Rsp::VerifiedAmounts).unwrap();
 
     try_join(alice_swap, bob_swap).await.unwrap();
+
+    let btc_alice_final = alice_btc_wallet.as_ref().balance().await.unwrap();
+    let btc_bob_final = bob_btc_wallet.as_ref().balance().await.unwrap();
+
+    let xmr_alice_final = alice_xmr_wallet.as_ref().get_balance().await.unwrap();
+
+    monero.wait_for_bob_wallet_block_height().await.unwrap();
+    let xmr_bob_final = bob_xmr_wallet.as_ref().get_balance().await.unwrap();
+
+    assert_eq!(
+        btc_alice_final,
+        btc_alice + btc - bitcoin::Amount::from_sat(xmr_btc::bitcoin::TX_FEE)
+    );
+    assert!(btc_bob_final <= btc_bob - btc);
+
+    assert!(xmr_alice_final.as_piconero() <= xmr_alice - xmr);
+    assert_eq!(xmr_bob_final.as_piconero(), xmr_bob + xmr);
 }