Support fee overpayment by 1 msat in expect_payment_forwarded test util.

See ClaimAlongRouteArgs::allow_1_msat_fee_overpay.

Author: valentinewallace

lightning/src/ln/chanmon_update_fail_tests.rs

@@ -3404,7 +3404,7 @@ fn do_test_reload_mon_update_completion_actions(close_during_reload: bool) {
 	let bc_update_id = nodes[1].chain_monitor.latest_monitor_update_id.lock().unwrap().get(&chan_id_bc).unwrap().2;
 	let mut events = nodes[1].node.get_and_clear_pending_events();
 	assert_eq!(events.len(), if close_during_reload { 2 } else { 1 });
-	expect_payment_forwarded(events.pop().unwrap(), &nodes[1], &nodes[0], &nodes[2], Some(1000), close_during_reload, false);
+	expect_payment_forwarded(events.pop().unwrap(), &nodes[1], &nodes[0], &nodes[2], Some(1000), close_during_reload, false, false);
 	if close_during_reload {
 		match events[0] {
 			Event::ChannelClosed { .. } => {},

lightning/src/ln/functional_test_utils.rs

@@ -2167,14 +2167,21 @@ macro_rules! expect_payment_path_successful {
 
 pub fn expect_payment_forwarded<CM: AChannelManager, H: NodeHolder<CM=CM>>(
 	event: Event, node: &H, prev_node: &H, next_node: &H, expected_fee: Option<u64>,
-	upstream_force_closed: bool, downstream_force_closed: bool
-) {
+	upstream_force_closed: bool, downstream_force_closed: bool, allow_1_msat_fee_overpay: bool,
+) -> Option<u64> {
 	match event {
 		Event::PaymentForwarded {
 			fee_earned_msat, prev_channel_id, claim_from_onchain_tx, next_channel_id,
 			outbound_amount_forwarded_msat: _
 		} => {
-			assert_eq!(fee_earned_msat, expected_fee);
+			if allow_1_msat_fee_overpay {
+				// Aggregating fees for blinded paths may result in a rounding error, causing slight
+				// overpayment in fees.
+				assert!(fee_earned_msat.unwrap() == expected_fee.unwrap()
+					|| fee_earned_msat.unwrap() == expected_fee.unwrap() + 1);
+			} else {
+				assert_eq!(fee_earned_msat, expected_fee);
+			}
 			if !upstream_force_closed {
 				// Is the event prev_channel_id in one of the channels between the two nodes?
 				assert!(node.node().list_channels().iter().any(|x| x.counterparty.node_id == prev_node.node().get_our_node_id() && x.channel_id == prev_channel_id.unwrap()));
@@ -2185,6 +2192,7 @@ pub fn expect_payment_forwarded<CM: AChannelManager, H: NodeHolder<CM=CM>>(
 				assert!(node.node().list_channels().iter().any(|x| x.counterparty.node_id == next_node.node().get_our_node_id() && x.channel_id == next_channel_id.unwrap()));
 			}
 			assert_eq!(claim_from_onchain_tx, downstream_force_closed);
+			fee_earned_msat
 		},
 		_ => panic!("Unexpected event"),
 	}
@@ -2196,7 +2204,7 @@ macro_rules! expect_payment_forwarded {
 		assert_eq!(events.len(), 1);
 		$crate::ln::functional_test_utils::expect_payment_forwarded(
 			events.pop().unwrap(), &$node, &$prev_node, &$next_node, $expected_fee,
-			$upstream_force_closed, $downstream_force_closed);
+			$upstream_force_closed, $downstream_force_closed, false);
 	}
 }