_ Git - rust-lightning/blob - lightning-invoice/src/payment.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! A module for paying Lightning invoices.
  11 //!
  12 //! Defines an [`InvoicePayer`] utility for paying invoices, parameterized by [`Payer`] and
  13 //! [`Router`] traits. Implementations of [`Payer`] provide the payer's node id, channels, and means
  14 //! to send a payment over a [`Route`]. Implementations of [`Router`] find a [`Route`] between payer
  15 //! and payee using information provided by the payer and from the payee's [`Invoice`].
  16 //!
  17 //! [`InvoicePayer`] is capable of retrying failed payments. It accomplishes this by implementing
  18 //! [`EventHandler`] which decorates a user-provided handler. It will intercept any
  19 //! [`Event::PaymentPathFailed`] events and retry the failed paths for a fixed number of total
  20 //! attempts or until retry is no longer possible. In such a situation, [`InvoicePayer`] will pass
  21 //! along the events to the user-provided handler.
  22 //!
  23 //! # Example
  24 //!
  25 //! ```
  26 //! # extern crate lightning;
  27 //! # extern crate lightning_invoice;
  28 //! # extern crate secp256k1;
  29 //! #
  30 //! # use lightning::ln::{PaymentHash, PaymentSecret};
  31 //! # use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
  32 //! # use lightning::ln::msgs::LightningError;
  33 //! # use lightning::routing;
  34 //! # use lightning::routing::network_graph::NodeId;
  35 //! # use lightning::routing::router::{Route, RouteHop, RouteParameters};
  36 //! # use lightning::util::events::{Event, EventHandler, EventsProvider};
  37 //! # use lightning::util::logger::{Logger, Record};
  38 //! # use lightning_invoice::Invoice;
  39 //! # use lightning_invoice::payment::{InvoicePayer, Payer, RetryAttempts, Router};
  40 //! # use secp256k1::key::PublicKey;
  41 //! # use std::cell::RefCell;
  42 //! # use std::ops::Deref;
  43 //! #
  44 //! # struct FakeEventProvider {}
  45 //! # impl EventsProvider for FakeEventProvider {
  46 //! #     fn process_pending_events<H: Deref>(&self, handler: H) where H::Target: EventHandler {}
  47 //! # }
  48 //! #
  49 //! # struct FakePayer {}
  50 //! # impl Payer for FakePayer {
  51 //! #     fn node_id(&self) -> PublicKey { unimplemented!() }
  52 //! #     fn first_hops(&self) -> Vec<ChannelDetails> { unimplemented!() }
  53 //! #     fn send_payment(
  54 //! #         &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
  55 //! #     ) -> Result<PaymentId, PaymentSendFailure> { unimplemented!() }
  56 //! #     fn retry_payment(
  57 //! #         &self, route: &Route, payment_id: PaymentId
  58 //! #     ) -> Result<(), PaymentSendFailure> { unimplemented!() }
  59 //! # }
  60 //! #
  61 //! # struct FakeRouter {};
  62 //! # impl<S: routing::Score> Router<S> for FakeRouter {
  63 //! #     fn find_route(
  64 //! #         &self, payer: &PublicKey, params: &RouteParameters,
  65 //! #         first_hops: Option<&[&ChannelDetails]>, scorer: &S
  66 //! #     ) -> Result<Route, LightningError> { unimplemented!() }
  67 //! # }
  68 //! #
  69 //! # struct FakeScorer {};
  70 //! # impl routing::Score for FakeScorer {
  71 //! #     fn channel_penalty_msat(
  72 //! #         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
  73 //! #     ) -> u64 { 0 }
  74 //! #     fn payment_path_failed(&mut self, _path: &Vec<RouteHop>, _short_channel_id: u64) {}
  75 //! # }
  76 //! #
  77 //! # struct FakeLogger {};
  78 //! # impl Logger for FakeLogger {
  79 //! #     fn log(&self, record: &Record) { unimplemented!() }
  80 //! # }
  81 //! #
  82 //! # fn main() {
  83 //! let event_handler = |event: &Event| {
  84 //!     match event {
  85 //!         Event::PaymentPathFailed { .. } => println!("payment failed after retries"),
  86 //!         Event::PaymentSent { .. } => println!("payment successful"),
  87 //!         _ => {},
  88 //!     }
  89 //! };
  90 //! # let payer = FakePayer {};
  91 //! # let router = FakeRouter {};
  92 //! # let scorer = RefCell::new(FakeScorer {});
  93 //! # let logger = FakeLogger {};
  94 //! let invoice_payer = InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
  95 //!
  96 //! let invoice = "...";
  97 //! let invoice = invoice.parse::<Invoice>().unwrap();
  98 //! invoice_payer.pay_invoice(&invoice).unwrap();
  99 //!
 100 //! # let event_provider = FakeEventProvider {};
 101 //! loop {
 102 //!     event_provider.process_pending_events(&invoice_payer);
 103 //! }
 104 //! # }
 105 //! ```
 106 //!
 107 //! # Note
 108 //!
 109 //! The [`Route`] is computed before each payment attempt. Any updates affecting path finding such
 110 //! as updates to the network graph or changes to channel scores should be applied prior to
 111 //! retries, typically by way of composing [`EventHandler`]s accordingly.
 112
 113 use crate::Invoice;
 114
 115 use bitcoin_hashes::Hash;
 116
 117 use lightning::ln::{PaymentHash, PaymentSecret};
 118 use lightning::ln::channelmanager::{ChannelDetails, PaymentId, PaymentSendFailure};
 119 use lightning::ln::msgs::LightningError;
 120 use lightning::routing;
 121 use lightning::routing::{LockableScore, Score};
 122 use lightning::routing::router::{Payee, Route, RouteParameters};
 123 use lightning::util::events::{Event, EventHandler};
 124 use lightning::util::logger::Logger;
 125
 126 use secp256k1::key::PublicKey;
 127
 128 use std::collections::hash_map::{self, HashMap};
 129 use std::ops::Deref;
 130 use std::sync::Mutex;
 131 use std::time::{Duration, SystemTime};
 132
 133 /// A utility for paying [`Invoice]`s.
 134 pub struct InvoicePayer<P: Deref, R, S: Deref, L: Deref, E>
 135 where
 136         P::Target: Payer,
 137         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 138         S::Target: for <'a> routing::LockableScore<'a>,
 139         L::Target: Logger,
 140         E: EventHandler,
 141 {
 142         payer: P,
 143         router: R,
 144         scorer: S,
 145         logger: L,
 146         event_handler: E,
 147         payment_cache: Mutex<HashMap<PaymentHash, usize>>,
 148         retry_attempts: RetryAttempts,
 149 }
 150
 151 /// A trait defining behavior of an [`Invoice`] payer.
 152 pub trait Payer {
 153         /// Returns the payer's node id.
 154         fn node_id(&self) -> PublicKey;
 155
 156         /// Returns the payer's channels.
 157         fn first_hops(&self) -> Vec<ChannelDetails>;
 158
 159         /// Sends a payment over the Lightning Network using the given [`Route`].
 160         fn send_payment(
 161                 &self, route: &Route, payment_hash: PaymentHash, payment_secret: &Option<PaymentSecret>
 162         ) -> Result<PaymentId, PaymentSendFailure>;
 163
 164         /// Retries a failed payment path for the [`PaymentId`] using the given [`Route`].
 165         fn retry_payment(&self, route: &Route, payment_id: PaymentId) -> Result<(), PaymentSendFailure>;
 166 }
 167
 168 /// A trait defining behavior for routing an [`Invoice`] payment.
 169 pub trait Router<S: routing::Score> {
 170         /// Finds a [`Route`] between `payer` and `payee` for a payment with the given values.
 171         fn find_route(
 172                 &self, payer: &PublicKey, params: &RouteParameters, first_hops: Option<&[&ChannelDetails]>,
 173                 scorer: &S
 174         ) -> Result<Route, LightningError>;
 175 }
 176
 177 /// Number of attempts to retry payment path failures for an [`Invoice`].
 178 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 179 pub struct RetryAttempts(pub usize);
 180
 181 /// An error that may occur when making a payment.
 182 #[derive(Clone, Debug)]
 183 pub enum PaymentError {
 184         /// An error resulting from the provided [`Invoice`] or payment hash.
 185         Invoice(&'static str),
 186         /// An error occurring when finding a route.
 187         Routing(LightningError),
 188         /// An error occurring when sending a payment.
 189         Sending(PaymentSendFailure),
 190 }
 191
 192 impl<P: Deref, R, S: Deref, L: Deref, E> InvoicePayer<P, R, S, L, E>
 193 where
 194         P::Target: Payer,
 195         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 196         S::Target: for <'a> routing::LockableScore<'a>,
 197         L::Target: Logger,
 198         E: EventHandler,
 199 {
 200         /// Creates an invoice payer that retries failed payment paths.
 201         ///
 202         /// Will forward any [`Event::PaymentPathFailed`] events to the decorated `event_handler` once
 203         /// `retry_attempts` has been exceeded for a given [`Invoice`].
 204         pub fn new(
 205                 payer: P, router: R, scorer: S, logger: L, event_handler: E, retry_attempts: RetryAttempts
 206         ) -> Self {
 207                 Self {
 208                         payer,
 209                         router,
 210                         scorer,
 211                         logger,
 212                         event_handler,
 213                         payment_cache: Mutex::new(HashMap::new()),
 214                         retry_attempts,
 215                 }
 216         }
 217
 218         /// Pays the given [`Invoice`], caching it for later use in case a retry is needed.
 219         pub fn pay_invoice(&self, invoice: &Invoice) -> Result<PaymentId, PaymentError> {
 220                 if invoice.amount_milli_satoshis().is_none() {
 221                         Err(PaymentError::Invoice("amount missing"))
 222                 } else {
 223                         self.pay_invoice_internal(invoice, None)
 224                 }
 225         }
 226
 227         /// Pays the given zero-value [`Invoice`] using the given amount, caching it for later use in
 228         /// case a retry is needed.
 229         pub fn pay_zero_value_invoice(
 230                 &self, invoice: &Invoice, amount_msats: u64
 231         ) -> Result<PaymentId, PaymentError> {
 232                 if invoice.amount_milli_satoshis().is_some() {
 233                         Err(PaymentError::Invoice("amount unexpected"))
 234                 } else {
 235                         self.pay_invoice_internal(invoice, Some(amount_msats))
 236                 }
 237         }
 238
 239         fn pay_invoice_internal(
 240                 &self, invoice: &Invoice, amount_msats: Option<u64>
 241         ) -> Result<PaymentId, PaymentError> {
 242                 debug_assert!(invoice.amount_milli_satoshis().is_some() ^ amount_msats.is_some());
 243                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 244                 let mut payment_cache = self.payment_cache.lock().unwrap();
 245                 match payment_cache.entry(payment_hash) {
 246                         hash_map::Entry::Vacant(entry) => {
 247                                 let payer = self.payer.node_id();
 248                                 let mut payee = Payee::new(invoice.recover_payee_pub_key())
 249                                         .with_expiry_time(expiry_time_from_unix_epoch(&invoice).as_secs())
 250                                         .with_route_hints(invoice.route_hints());
 251                                 if let Some(features) = invoice.features() {
 252                                         payee = payee.with_features(features.clone());
 253                                 }
 254                                 let params = RouteParameters {
 255                                         payee,
 256                                         final_value_msat: invoice.amount_milli_satoshis().or(amount_msats).unwrap(),
 257                                         final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 258                                 };
 259                                 let first_hops = self.payer.first_hops();
 260                                 let route = self.router.find_route(
 261                                         &payer,
 262                                         &params,
 263                                         Some(&first_hops.iter().collect::<Vec<_>>()),
 264                                         &self.scorer.lock(),
 265                                 ).map_err(|e| PaymentError::Routing(e))?;
 266
 267                                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 268                                 let payment_secret = Some(invoice.payment_secret().clone());
 269                                 let payment_id = self.payer.send_payment(&route, payment_hash, &payment_secret)
 270                                         .map_err(|e| PaymentError::Sending(e))?;
 271                                 entry.insert(0);
 272                                 Ok(payment_id)
 273                         },
 274                         hash_map::Entry::Occupied(_) => Err(PaymentError::Invoice("payment pending")),
 275                 }
 276         }
 277
 278         fn retry_payment(
 279                 &self, payment_id: PaymentId, params: &RouteParameters
 280         ) -> Result<(), PaymentError> {
 281                 let payer = self.payer.node_id();
 282                 let first_hops = self.payer.first_hops();
 283                 let route = self.router.find_route(
 284                         &payer, &params, Some(&first_hops.iter().collect::<Vec<_>>()),
 285                         &self.scorer.lock()
 286                 ).map_err(|e| PaymentError::Routing(e))?;
 287                 self.payer.retry_payment(&route, payment_id).map_err(|e| PaymentError::Sending(e))
 288         }
 289
 290         /// Removes the payment cached by the given payment hash.
 291         ///
 292         /// Should be called once a payment has failed or succeeded if not using [`InvoicePayer`] as an
 293         /// [`EventHandler`]. Otherwise, calling this method is unnecessary.
 294         pub fn remove_cached_payment(&self, payment_hash: &PaymentHash) {
 295                 self.payment_cache.lock().unwrap().remove(payment_hash);
 296         }
 297 }
 298
 299 fn expiry_time_from_unix_epoch(invoice: &Invoice) -> Duration {
 300         invoice.timestamp().duration_since(SystemTime::UNIX_EPOCH).unwrap() + invoice.expiry_time()
 301 }
 302
 303 fn has_expired(params: &RouteParameters) -> bool {
 304         let expiry_time = Duration::from_secs(params.payee.expiry_time.unwrap());
 305         Invoice::is_expired_from_epoch(&SystemTime::UNIX_EPOCH, expiry_time)
 306 }
 307
 308 impl<P: Deref, R, S: Deref, L: Deref, E> EventHandler for InvoicePayer<P, R, S, L, E>
 309 where
 310         P::Target: Payer,
 311         R: for <'a> Router<<<S as Deref>::Target as routing::LockableScore<'a>>::Locked>,
 312         S::Target: for <'a> routing::LockableScore<'a>,
 313         L::Target: Logger,
 314         E: EventHandler,
 315 {
 316         fn handle_event(&self, event: &Event) {
 317                 match event {
 318                         Event::PaymentPathFailed {
 319                                 payment_id, payment_hash, rejected_by_dest, path, short_channel_id, retry, ..
 320                         } => {
 321                                 if let Some(short_channel_id) = short_channel_id {
 322                                         self.scorer.lock().payment_path_failed(path, *short_channel_id);
 323                                 }
 324
 325                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 326                                 let entry = loop {
 327                                         let entry = payment_cache.entry(*payment_hash);
 328                                         match entry {
 329                                                 hash_map::Entry::Occupied(_) => break entry,
 330                                                 hash_map::Entry::Vacant(entry) => entry.insert(0),
 331                                         };
 332                                 };
 333                                 if let hash_map::Entry::Occupied(mut entry) = entry {
 334                                         let max_payment_attempts = self.retry_attempts.0 + 1;
 335                                         let attempts = entry.get_mut();
 336                                         *attempts += 1;
 337
 338                                         if *rejected_by_dest {
 339                                                 log_trace!(self.logger, "Payment {} rejected by destination; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 340                                         } else if payment_id.is_none() {
 341                                                 log_trace!(self.logger, "Payment {} has no id; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 342                                         } else if *attempts >= max_payment_attempts {
 343                                                 log_trace!(self.logger, "Payment {} exceeded maximum attempts; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 344                                         } else if retry.is_none() {
 345                                                 log_trace!(self.logger, "Payment {} missing retry params; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 346                                         } else if has_expired(retry.as_ref().unwrap()) {
 347                                                 log_trace!(self.logger, "Invoice expired for payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 348                                         } else if self.retry_payment(*payment_id.as_ref().unwrap(), retry.as_ref().unwrap()).is_err() {
 349                                                 log_trace!(self.logger, "Error retrying payment {}; not retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 350                                         } else {
 351                                                 log_trace!(self.logger, "Payment {} failed; retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 352                                                 return;
 353                                         }
 354
 355                                         // Either the payment was rejected, the maximum attempts were exceeded, or an
 356                                         // error occurred when attempting to retry.
 357                                         entry.remove();
 358                                 } else {
 359                                         unreachable!();
 360                                 }
 361                         },
 362                         Event::PaymentSent { payment_hash, .. } => {
 363                                 let mut payment_cache = self.payment_cache.lock().unwrap();
 364                                 let attempts = payment_cache
 365                                         .remove(payment_hash)
 366                                         .map_or(1, |attempts| attempts + 1);
 367                                 log_trace!(self.logger, "Payment {} succeeded (attempts: {})", log_bytes!(payment_hash.0), attempts);
 368                         },
 369                         _ => {},
 370                 }
 371
 372                 // Delegate to the decorated event handler unless the payment is retried.
 373                 self.event_handler.handle_event(event)
 374         }
 375 }
 376
 377 #[cfg(test)]
 378 mod tests {
 379         use super::*;
 380         use crate::{DEFAULT_EXPIRY_TIME, InvoiceBuilder, Currency};
 381         use bitcoin_hashes::sha256::Hash as Sha256;
 382         use lightning::ln::PaymentPreimage;
 383         use lightning::ln::features::{ChannelFeatures, NodeFeatures};
 384         use lightning::ln::msgs::{ErrorAction, LightningError};
 385         use lightning::routing::network_graph::NodeId;
 386         use lightning::routing::router::{Payee, Route, RouteHop};
 387         use lightning::util::test_utils::TestLogger;
 388         use lightning::util::errors::APIError;
 389         use lightning::util::events::Event;
 390         use secp256k1::{SecretKey, PublicKey, Secp256k1};
 391         use std::cell::RefCell;
 392         use std::time::{SystemTime, Duration};
 393
 394         fn invoice(payment_preimage: PaymentPreimage) -> Invoice {
 395                 let payment_hash = Sha256::hash(&payment_preimage.0);
 396                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 397                 InvoiceBuilder::new(Currency::Bitcoin)
 398                         .description("test".into())
 399                         .payment_hash(payment_hash)
 400                         .payment_secret(PaymentSecret([0; 32]))
 401                         .current_timestamp()
 402                         .min_final_cltv_expiry(144)
 403                         .amount_milli_satoshis(128)
 404                         .build_signed(|hash| {
 405                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 406                         })
 407                         .unwrap()
 408         }
 409
 410         fn zero_value_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 411                 let payment_hash = Sha256::hash(&payment_preimage.0);
 412                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 413                 InvoiceBuilder::new(Currency::Bitcoin)
 414                         .description("test".into())
 415                         .payment_hash(payment_hash)
 416                         .payment_secret(PaymentSecret([0; 32]))
 417                         .current_timestamp()
 418                         .min_final_cltv_expiry(144)
 419                         .build_signed(|hash| {
 420                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 421                         })
 422                         .unwrap()
 423         }
 424
 425         fn expired_invoice(payment_preimage: PaymentPreimage) -> Invoice {
 426                 let payment_hash = Sha256::hash(&payment_preimage.0);
 427                 let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
 428                 let timestamp = SystemTime::now()
 429                         .checked_sub(Duration::from_secs(DEFAULT_EXPIRY_TIME * 2))
 430                         .unwrap();
 431                 InvoiceBuilder::new(Currency::Bitcoin)
 432                         .description("test".into())
 433                         .payment_hash(payment_hash)
 434                         .payment_secret(PaymentSecret([0; 32]))
 435                         .timestamp(timestamp)
 436                         .min_final_cltv_expiry(144)
 437                         .amount_milli_satoshis(128)
 438                         .build_signed(|hash| {
 439                                 Secp256k1::new().sign_recoverable(hash, &private_key)
 440                         })
 441                         .unwrap()
 442         }
 443
 444         #[test]
 445         fn pays_invoice_on_first_attempt() {
 446                 let event_handled = core::cell::RefCell::new(false);
 447                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 448
 449                 let payment_preimage = PaymentPreimage([1; 32]);
 450                 let invoice = invoice(payment_preimage);
 451                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 452
 453                 let payer = TestPayer::new();
 454                 let router = TestRouter {};
 455                 let scorer = RefCell::new(TestScorer::new());
 456                 let logger = TestLogger::new();
 457                 let invoice_payer =
 458                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 459
 460                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 461                 assert_eq!(*payer.attempts.borrow(), 1);
 462
 463                 invoice_payer.handle_event(&Event::PaymentSent {
 464                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 465                 });
 466                 assert_eq!(*event_handled.borrow(), true);
 467                 assert_eq!(*payer.attempts.borrow(), 1);
 468         }
 469
 470         #[test]
 471         fn pays_invoice_on_retry() {
 472                 let event_handled = core::cell::RefCell::new(false);
 473                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 474
 475                 let payment_preimage = PaymentPreimage([1; 32]);
 476                 let invoice = invoice(payment_preimage);
 477                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 478                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 479
 480                 let payer = TestPayer::new()
 481                         .expect_value_msat(final_value_msat)
 482                         .expect_value_msat(final_value_msat / 2);
 483                 let router = TestRouter {};
 484                 let scorer = RefCell::new(TestScorer::new());
 485                 let logger = TestLogger::new();
 486                 let invoice_payer =
 487                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 488
 489                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 490                 assert_eq!(*payer.attempts.borrow(), 1);
 491
 492                 let event = Event::PaymentPathFailed {
 493                         payment_id,
 494                         payment_hash,
 495                         network_update: None,
 496                         rejected_by_dest: false,
 497                         all_paths_failed: false,
 498                         path: TestRouter::path_for_value(final_value_msat),
 499                         short_channel_id: None,
 500                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 501                 };
 502                 invoice_payer.handle_event(&event);
 503                 assert_eq!(*event_handled.borrow(), false);
 504                 assert_eq!(*payer.attempts.borrow(), 2);
 505
 506                 invoice_payer.handle_event(&Event::PaymentSent {
 507                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 508                 });
 509                 assert_eq!(*event_handled.borrow(), true);
 510                 assert_eq!(*payer.attempts.borrow(), 2);
 511         }
 512
 513         #[test]
 514         fn retries_payment_path_for_unknown_payment() {
 515                 let event_handled = core::cell::RefCell::new(false);
 516                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 517
 518                 let payment_preimage = PaymentPreimage([1; 32]);
 519                 let invoice = invoice(payment_preimage);
 520                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 521                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 522
 523                 let payer = TestPayer::new();
 524                 let router = TestRouter {};
 525                 let scorer = RefCell::new(TestScorer::new());
 526                 let logger = TestLogger::new();
 527                 let invoice_payer =
 528                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 529
 530                 let payment_id = Some(PaymentId([1; 32]));
 531                 let event = Event::PaymentPathFailed {
 532                         payment_id,
 533                         payment_hash,
 534                         network_update: None,
 535                         rejected_by_dest: false,
 536                         all_paths_failed: false,
 537                         path: TestRouter::path_for_value(final_value_msat),
 538                         short_channel_id: None,
 539                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 540                 };
 541                 invoice_payer.handle_event(&event);
 542                 assert_eq!(*event_handled.borrow(), false);
 543                 assert_eq!(*payer.attempts.borrow(), 1);
 544
 545                 invoice_payer.handle_event(&event);
 546                 assert_eq!(*event_handled.borrow(), false);
 547                 assert_eq!(*payer.attempts.borrow(), 2);
 548
 549                 invoice_payer.handle_event(&Event::PaymentSent {
 550                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 551                 });
 552                 assert_eq!(*event_handled.borrow(), true);
 553                 assert_eq!(*payer.attempts.borrow(), 2);
 554         }
 555
 556         #[test]
 557         fn fails_paying_invoice_after_max_retries() {
 558                 let event_handled = core::cell::RefCell::new(false);
 559                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 560
 561                 let payment_preimage = PaymentPreimage([1; 32]);
 562                 let invoice = invoice(payment_preimage);
 563                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 564
 565                 let payer = TestPayer::new()
 566                         .expect_value_msat(final_value_msat)
 567                         .expect_value_msat(final_value_msat / 2)
 568                         .expect_value_msat(final_value_msat / 2);
 569                 let router = TestRouter {};
 570                 let scorer = RefCell::new(TestScorer::new());
 571                 let logger = TestLogger::new();
 572                 let invoice_payer =
 573                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 574
 575                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 576                 assert_eq!(*payer.attempts.borrow(), 1);
 577
 578                 let event = Event::PaymentPathFailed {
 579                         payment_id,
 580                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 581                         network_update: None,
 582                         rejected_by_dest: false,
 583                         all_paths_failed: true,
 584                         path: TestRouter::path_for_value(final_value_msat),
 585                         short_channel_id: None,
 586                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 587                 };
 588                 invoice_payer.handle_event(&event);
 589                 assert_eq!(*event_handled.borrow(), false);
 590                 assert_eq!(*payer.attempts.borrow(), 2);
 591
 592                 let event = Event::PaymentPathFailed {
 593                         payment_id,
 594                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 595                         network_update: None,
 596                         rejected_by_dest: false,
 597                         all_paths_failed: false,
 598                         path: TestRouter::path_for_value(final_value_msat / 2),
 599                         short_channel_id: None,
 600                         retry: Some(RouteParameters {
 601                                 final_value_msat: final_value_msat / 2, ..TestRouter::retry_for_invoice(&invoice)
 602                         }),
 603                 };
 604                 invoice_payer.handle_event(&event);
 605                 assert_eq!(*event_handled.borrow(), false);
 606                 assert_eq!(*payer.attempts.borrow(), 3);
 607
 608                 invoice_payer.handle_event(&event);
 609                 assert_eq!(*event_handled.borrow(), true);
 610                 assert_eq!(*payer.attempts.borrow(), 3);
 611         }
 612
 613         #[test]
 614         fn fails_paying_invoice_with_missing_retry_params() {
 615                 let event_handled = core::cell::RefCell::new(false);
 616                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 617
 618                 let payer = TestPayer::new();
 619                 let router = TestRouter {};
 620                 let scorer = RefCell::new(TestScorer::new());
 621                 let logger = TestLogger::new();
 622                 let invoice_payer =
 623                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 624
 625                 let payment_preimage = PaymentPreimage([1; 32]);
 626                 let invoice = invoice(payment_preimage);
 627                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 628                 assert_eq!(*payer.attempts.borrow(), 1);
 629
 630                 let event = Event::PaymentPathFailed {
 631                         payment_id,
 632                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 633                         network_update: None,
 634                         rejected_by_dest: false,
 635                         all_paths_failed: false,
 636                         path: vec![],
 637                         short_channel_id: None,
 638                         retry: None,
 639                 };
 640                 invoice_payer.handle_event(&event);
 641                 assert_eq!(*event_handled.borrow(), true);
 642                 assert_eq!(*payer.attempts.borrow(), 1);
 643         }
 644
 645         #[test]
 646         fn fails_paying_invoice_after_expiration() {
 647                 let event_handled = core::cell::RefCell::new(false);
 648                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 649
 650                 let payer = TestPayer::new();
 651                 let router = TestRouter {};
 652                 let scorer = RefCell::new(TestScorer::new());
 653                 let logger = TestLogger::new();
 654                 let invoice_payer =
 655                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 656
 657                 let payment_preimage = PaymentPreimage([1; 32]);
 658                 let invoice = expired_invoice(payment_preimage);
 659                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 660                 assert_eq!(*payer.attempts.borrow(), 1);
 661
 662                 let event = Event::PaymentPathFailed {
 663                         payment_id,
 664                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 665                         network_update: None,
 666                         rejected_by_dest: false,
 667                         all_paths_failed: false,
 668                         path: vec![],
 669                         short_channel_id: None,
 670                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 671                 };
 672                 invoice_payer.handle_event(&event);
 673                 assert_eq!(*event_handled.borrow(), true);
 674                 assert_eq!(*payer.attempts.borrow(), 1);
 675         }
 676
 677         #[test]
 678         fn fails_paying_invoice_after_retry_error() {
 679                 let event_handled = core::cell::RefCell::new(false);
 680                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 681
 682                 let payment_preimage = PaymentPreimage([1; 32]);
 683                 let invoice = invoice(payment_preimage);
 684                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 685
 686                 let payer = TestPayer::new()
 687                         .fails_on_attempt(2)
 688                         .expect_value_msat(final_value_msat);
 689                 let router = TestRouter {};
 690                 let scorer = RefCell::new(TestScorer::new());
 691                 let logger = TestLogger::new();
 692                 let invoice_payer =
 693                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 694
 695                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 696                 assert_eq!(*payer.attempts.borrow(), 1);
 697
 698                 let event = Event::PaymentPathFailed {
 699                         payment_id,
 700                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 701                         network_update: None,
 702                         rejected_by_dest: false,
 703                         all_paths_failed: false,
 704                         path: TestRouter::path_for_value(final_value_msat / 2),
 705                         short_channel_id: None,
 706                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 707                 };
 708                 invoice_payer.handle_event(&event);
 709                 assert_eq!(*event_handled.borrow(), true);
 710                 assert_eq!(*payer.attempts.borrow(), 2);
 711         }
 712
 713         #[test]
 714         fn fails_paying_invoice_after_rejected_by_payee() {
 715                 let event_handled = core::cell::RefCell::new(false);
 716                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 717
 718                 let payer = TestPayer::new();
 719                 let router = TestRouter {};
 720                 let scorer = RefCell::new(TestScorer::new());
 721                 let logger = TestLogger::new();
 722                 let invoice_payer =
 723                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 724
 725                 let payment_preimage = PaymentPreimage([1; 32]);
 726                 let invoice = invoice(payment_preimage);
 727                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 728                 assert_eq!(*payer.attempts.borrow(), 1);
 729
 730                 let event = Event::PaymentPathFailed {
 731                         payment_id,
 732                         payment_hash: PaymentHash(invoice.payment_hash().clone().into_inner()),
 733                         network_update: None,
 734                         rejected_by_dest: true,
 735                         all_paths_failed: false,
 736                         path: vec![],
 737                         short_channel_id: None,
 738                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 739                 };
 740                 invoice_payer.handle_event(&event);
 741                 assert_eq!(*event_handled.borrow(), true);
 742                 assert_eq!(*payer.attempts.borrow(), 1);
 743         }
 744
 745         #[test]
 746         fn fails_repaying_invoice_with_pending_payment() {
 747                 let event_handled = core::cell::RefCell::new(false);
 748                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 749
 750                 let payer = TestPayer::new();
 751                 let router = TestRouter {};
 752                 let scorer = RefCell::new(TestScorer::new());
 753                 let logger = TestLogger::new();
 754                 let invoice_payer =
 755                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 756
 757                 let payment_preimage = PaymentPreimage([1; 32]);
 758                 let invoice = invoice(payment_preimage);
 759                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 760
 761                 // Cannot repay an invoice pending payment.
 762                 match invoice_payer.pay_invoice(&invoice) {
 763                         Err(PaymentError::Invoice("payment pending")) => {},
 764                         Err(_) => panic!("unexpected error"),
 765                         Ok(_) => panic!("expected invoice error"),
 766                 }
 767
 768                 // Can repay an invoice once cleared from cache.
 769                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 770                 invoice_payer.remove_cached_payment(&payment_hash);
 771                 assert!(invoice_payer.pay_invoice(&invoice).is_ok());
 772
 773                 // Cannot retry paying an invoice if cleared from cache.
 774                 invoice_payer.remove_cached_payment(&payment_hash);
 775                 let event = Event::PaymentPathFailed {
 776                         payment_id,
 777                         payment_hash,
 778                         network_update: None,
 779                         rejected_by_dest: false,
 780                         all_paths_failed: false,
 781                         path: vec![],
 782                         short_channel_id: None,
 783                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 784                 };
 785                 invoice_payer.handle_event(&event);
 786                 assert_eq!(*event_handled.borrow(), true);
 787         }
 788
 789         #[test]
 790         fn fails_paying_invoice_with_routing_errors() {
 791                 let payer = TestPayer::new();
 792                 let router = FailingRouter {};
 793                 let scorer = RefCell::new(TestScorer::new());
 794                 let logger = TestLogger::new();
 795                 let invoice_payer =
 796                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 797
 798                 let payment_preimage = PaymentPreimage([1; 32]);
 799                 let invoice = invoice(payment_preimage);
 800                 match invoice_payer.pay_invoice(&invoice) {
 801                         Err(PaymentError::Routing(_)) => {},
 802                         Err(_) => panic!("unexpected error"),
 803                         Ok(_) => panic!("expected routing error"),
 804                 }
 805         }
 806
 807         #[test]
 808         fn fails_paying_invoice_with_sending_errors() {
 809                 let payer = TestPayer::new().fails_on_attempt(1);
 810                 let router = TestRouter {};
 811                 let scorer = RefCell::new(TestScorer::new());
 812                 let logger = TestLogger::new();
 813                 let invoice_payer =
 814                         InvoicePayer::new(&payer, router, &scorer, &logger, |_: &_| {}, RetryAttempts(0));
 815
 816                 let payment_preimage = PaymentPreimage([1; 32]);
 817                 let invoice = invoice(payment_preimage);
 818                 match invoice_payer.pay_invoice(&invoice) {
 819                         Err(PaymentError::Sending(_)) => {},
 820                         Err(_) => panic!("unexpected error"),
 821                         Ok(_) => panic!("expected sending error"),
 822                 }
 823         }
 824
 825         #[test]
 826         fn pays_zero_value_invoice_using_amount() {
 827                 let event_handled = core::cell::RefCell::new(false);
 828                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 829
 830                 let payment_preimage = PaymentPreimage([1; 32]);
 831                 let invoice = zero_value_invoice(payment_preimage);
 832                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 833                 let final_value_msat = 100;
 834
 835                 let payer = TestPayer::new().expect_value_msat(final_value_msat);
 836                 let router = TestRouter {};
 837                 let scorer = RefCell::new(TestScorer::new());
 838                 let logger = TestLogger::new();
 839                 let invoice_payer =
 840                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 841
 842                 let payment_id =
 843                         Some(invoice_payer.pay_zero_value_invoice(&invoice, final_value_msat).unwrap());
 844                 assert_eq!(*payer.attempts.borrow(), 1);
 845
 846                 invoice_payer.handle_event(&Event::PaymentSent {
 847                         payment_id, payment_preimage, payment_hash, fee_paid_msat: None
 848                 });
 849                 assert_eq!(*event_handled.borrow(), true);
 850                 assert_eq!(*payer.attempts.borrow(), 1);
 851         }
 852
 853         #[test]
 854         fn fails_paying_zero_value_invoice_with_amount() {
 855                 let event_handled = core::cell::RefCell::new(false);
 856                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 857
 858                 let payer = TestPayer::new();
 859                 let router = TestRouter {};
 860                 let scorer = RefCell::new(TestScorer::new());
 861                 let logger = TestLogger::new();
 862                 let invoice_payer =
 863                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(0));
 864
 865                 let payment_preimage = PaymentPreimage([1; 32]);
 866                 let invoice = invoice(payment_preimage);
 867
 868                 // Cannot repay an invoice pending payment.
 869                 match invoice_payer.pay_zero_value_invoice(&invoice, 100) {
 870                         Err(PaymentError::Invoice("amount unexpected")) => {},
 871                         Err(_) => panic!("unexpected error"),
 872                         Ok(_) => panic!("expected invoice error"),
 873                 }
 874         }
 875
 876         #[test]
 877         fn scores_failed_channel() {
 878                 let event_handled = core::cell::RefCell::new(false);
 879                 let event_handler = |_: &_| { *event_handled.borrow_mut() = true; };
 880
 881                 let payment_preimage = PaymentPreimage([1; 32]);
 882                 let invoice = invoice(payment_preimage);
 883                 let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
 884                 let final_value_msat = invoice.amount_milli_satoshis().unwrap();
 885                 let path = TestRouter::path_for_value(final_value_msat);
 886                 let short_channel_id = Some(path[0].short_channel_id);
 887
 888                 // Expect that scorer is given short_channel_id upon handling the event.
 889                 let payer = TestPayer::new();
 890                 let router = TestRouter {};
 891                 let scorer = RefCell::new(TestScorer::new().expect_channel_failure(short_channel_id.unwrap()));
 892                 let logger = TestLogger::new();
 893                 let invoice_payer =
 894                         InvoicePayer::new(&payer, router, &scorer, &logger, event_handler, RetryAttempts(2));
 895
 896                 let payment_id = Some(invoice_payer.pay_invoice(&invoice).unwrap());
 897                 let event = Event::PaymentPathFailed {
 898                         payment_id,
 899                         payment_hash,
 900                         network_update: None,
 901                         rejected_by_dest: false,
 902                         all_paths_failed: false,
 903                         path,
 904                         short_channel_id,
 905                         retry: Some(TestRouter::retry_for_invoice(&invoice)),
 906                 };
 907                 invoice_payer.handle_event(&event);
 908         }
 909
 910         struct TestRouter;
 911
 912         impl TestRouter {
 913                 fn route_for_value(final_value_msat: u64) -> Route {
 914                         Route {
 915                                 paths: vec![
 916                                         vec![RouteHop {
 917                                                 pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
 918                                                 channel_features: ChannelFeatures::empty(),
 919                                                 node_features: NodeFeatures::empty(),
 920                                                 short_channel_id: 0, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 921                                         }],
 922                                         vec![RouteHop {
 923                                                 pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
 924                                                 channel_features: ChannelFeatures::empty(),
 925                                                 node_features: NodeFeatures::empty(),
 926                                                 short_channel_id: 1, fee_msat: final_value_msat / 2, cltv_expiry_delta: 144
 927                                         }],
 928                                 ],
 929                                 payee: None,
 930                         }
 931                 }
 932
 933                 fn path_for_value(final_value_msat: u64) -> Vec<RouteHop> {
 934                         TestRouter::route_for_value(final_value_msat).paths[0].clone()
 935                 }
 936
 937                 fn retry_for_invoice(invoice: &Invoice) -> RouteParameters {
 938                         let mut payee = Payee::new(invoice.recover_payee_pub_key())
 939                                 .with_expiry_time(expiry_time_from_unix_epoch(invoice).as_secs())
 940                                 .with_route_hints(invoice.route_hints());
 941                         if let Some(features) = invoice.features() {
 942                                 payee = payee.with_features(features.clone());
 943                         }
 944                         let final_value_msat = invoice.amount_milli_satoshis().unwrap() / 2;
 945                         RouteParameters {
 946                                 payee,
 947                                 final_value_msat,
 948                                 final_cltv_expiry_delta: invoice.min_final_cltv_expiry() as u32,
 949                         }
 950                 }
 951         }
 952
 953         impl<S: routing::Score> Router<S> for TestRouter {
 954                 fn find_route(
 955                         &self,
 956                         _payer: &PublicKey,
 957                         params: &RouteParameters,
 958                         _first_hops: Option<&[&ChannelDetails]>,
 959                         _scorer: &S,
 960                 ) -> Result<Route, LightningError> {
 961                         Ok(Route {
 962                                 payee: Some(params.payee.clone()), ..Self::route_for_value(params.final_value_msat)
 963                         })
 964                 }
 965         }
 966
 967         struct FailingRouter;
 968
 969         impl<S: routing::Score> Router<S> for FailingRouter {
 970                 fn find_route(
 971                         &self,
 972                         _payer: &PublicKey,
 973                         _params: &RouteParameters,
 974                         _first_hops: Option<&[&ChannelDetails]>,
 975                         _scorer: &S,
 976                 ) -> Result<Route, LightningError> {
 977                         Err(LightningError { err: String::new(), action: ErrorAction::IgnoreError })
 978                 }
 979         }
 980
 981         struct TestScorer {
 982                 expectations: std::collections::VecDeque<u64>,
 983         }
 984
 985         impl TestScorer {
 986                 fn new() -> Self {
 987                         Self {
 988                                 expectations: std::collections::VecDeque::new(),
 989                         }
 990                 }
 991
 992                 fn expect_channel_failure(mut self, short_channel_id: u64) -> Self {
 993                         self.expectations.push_back(short_channel_id);
 994                         self
 995                 }
 996         }
 997
 998         impl routing::Score for TestScorer {
 999                 fn channel_penalty_msat(
1000                         &self, _short_channel_id: u64, _source: &NodeId, _target: &NodeId
1001                 ) -> u64 { 0 }
1002
1003                 fn payment_path_failed(&mut self, _path: &Vec<RouteHop>, short_channel_id: u64) {
1004                         if let Some(expected_short_channel_id) = self.expectations.pop_front() {
1005                                 assert_eq!(short_channel_id, expected_short_channel_id);
1006                         }
1007                 }
1008         }
1009
1010         impl Drop for TestScorer {
1011                 fn drop(&mut self) {
1012                         if std::thread::panicking() {
1013                                 return;
1014                         }
1015
1016                         if !self.expectations.is_empty() {
1017                                 panic!("Unsatisfied channel failure expectations: {:?}", self.expectations);
1018                         }
1019                 }
1020         }
1021
1022         struct TestPayer {
1023                 expectations: core::cell::RefCell<std::collections::VecDeque<u64>>,
1024                 attempts: core::cell::RefCell<usize>,
1025                 failing_on_attempt: Option<usize>,
1026         }
1027
1028         impl TestPayer {
1029                 fn new() -> Self {
1030                         Self {
1031                                 expectations: core::cell::RefCell::new(std::collections::VecDeque::new()),
1032                                 attempts: core::cell::RefCell::new(0),
1033                                 failing_on_attempt: None,
1034                         }
1035                 }
1036
1037                 fn expect_value_msat(self, value_msat: u64) -> Self {
1038                         self.expectations.borrow_mut().push_back(value_msat);
1039                         self
1040                 }
1041
1042                 fn fails_on_attempt(self, attempt: usize) -> Self {
1043                         Self {
1044                                 expectations: core::cell::RefCell::new(self.expectations.borrow().clone()),
1045                                 attempts: core::cell::RefCell::new(0),
1046                                 failing_on_attempt: Some(attempt),
1047                         }
1048                 }
1049
1050                 fn check_attempts(&self) -> bool {
1051                         let mut attempts = self.attempts.borrow_mut();
1052                         *attempts += 1;
1053                         match self.failing_on_attempt {
1054                                 None => true,
1055                                 Some(attempt) if attempt != *attempts => true,
1056                                 Some(_) => false,
1057                         }
1058                 }
1059
1060                 fn check_value_msats(&self, route: &Route) {
1061                         let expected_value_msats = self.expectations.borrow_mut().pop_front();
1062                         if let Some(expected_value_msats) = expected_value_msats {
1063                                 let actual_value_msats = route.get_total_amount();
1064                                 assert_eq!(actual_value_msats, expected_value_msats);
1065                         }
1066                 }
1067         }
1068
1069         impl Drop for TestPayer {
1070                 fn drop(&mut self) {
1071                         if std::thread::panicking() {
1072                                 return;
1073                         }
1074
1075                         if !self.expectations.borrow().is_empty() {
1076                                 panic!("Unsatisfied payment expectations: {:?}", self.expectations.borrow());
1077                         }
1078                 }
1079         }
1080
1081         impl Payer for TestPayer {
1082                 fn node_id(&self) -> PublicKey {
1083                         let secp_ctx = Secp256k1::new();
1084                         PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap())
1085                 }
1086
1087                 fn first_hops(&self) -> Vec<ChannelDetails> {
1088                         Vec::new()
1089                 }
1090
1091                 fn send_payment(
1092                         &self,
1093                         route: &Route,
1094                         _payment_hash: PaymentHash,
1095                         _payment_secret: &Option<PaymentSecret>
1096                 ) -> Result<PaymentId, PaymentSendFailure> {
1097                         if self.check_attempts() {
1098                                 self.check_value_msats(route);
1099                                 Ok(PaymentId([1; 32]))
1100                         } else {
1101                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1102                         }
1103                 }
1104
1105                 fn retry_payment(
1106                         &self, route: &Route, _payment_id: PaymentId
1107                 ) -> Result<(), PaymentSendFailure> {
1108                         if self.check_attempts() {
1109                                 self.check_value_msats(route);
1110                                 Ok(())
1111                         } else {
1112                                 Err(PaymentSendFailure::ParameterError(APIError::MonitorUpdateFailed))
1113                         }
1114                 }
1115         }
1116 }