Expand test to cover Bolt11 custom TLVs

Extends the payment flow test to assert that custom TLVs passed to
`pay_for_bolt11_invoice` are preserved and delivered correctly.

Author: shaavan

lightning/src/ln/invoice_utils.rs

@@ -620,7 +620,8 @@ mod test {
 	};
 	use crate::ln::functional_test_utils::*;
 	use crate::ln::msgs::{BaseMessageHandler, ChannelMessageHandler, MessageSendEvent};
-	use crate::routing::router::{PaymentParameters, RouteParameters};
+	use crate::ln::outbound_payment::RecipientCustomTlvs;
+	use crate::routing::router::{PaymentParameters, RouteParameters, RouteParametersConfig};
 	use crate::sign::PhantomKeysManager;
 	use crate::types::payment::{PaymentHash, PaymentPreimage};
 	use crate::util::config::UserConfig;
@@ -663,26 +664,26 @@ mod test {
 	}
 
 	#[test]
-	fn create_and_pay_for_bolt11_invoice() {
+	fn create_and_pay_for_bolt11_invoice_with_custom_tlvs() {
 		let chanmon_cfgs = create_chanmon_cfgs(2);
 		let node_cfgs = create_node_cfgs(2, &chanmon_cfgs);
 		let node_chanmgrs = create_node_chanmgrs(2, &node_cfgs, &[None, None]);
 		let nodes = create_network(2, &node_cfgs, &node_chanmgrs);
 		create_unannounced_chan_between_nodes_with_value(&nodes, 0, 1, 100000, 10001);
 
-		let node_a_id = nodes[0].node.get_our_node_id();
-
+		let amt_msat = 10_000;
 		let description =
 			Bolt11InvoiceDescription::Direct(Description::new("test".to_string()).unwrap());
 		let non_default_invoice_expiry_secs = 4200;
+
 		let invoice_params = Bolt11InvoiceParameters {
-			amount_msats: Some(10_000),
+			amount_msats: Some(amt_msat),
 			description,
 			invoice_expiry_delta_secs: Some(non_default_invoice_expiry_secs),
 			..Default::default()
 		};
 		let invoice = nodes[1].node.create_bolt11_invoice(invoice_params).unwrap();
-		assert_eq!(invoice.amount_milli_satoshis(), Some(10_000));
+		assert_eq!(invoice.amount_milli_satoshis(), Some(amt_msat));
 		// If no `min_final_cltv_expiry_delta` is specified, then it should be `MIN_FINAL_CLTV_EXPIRY_DELTA`.
 		assert_eq!(invoice.min_final_cltv_expiry_delta(), MIN_FINAL_CLTV_EXPIRY_DELTA as u64);
 		assert_eq!(
@@ -694,6 +695,10 @@ mod test {
 			Duration::from_secs(non_default_invoice_expiry_secs.into())
 		);
 
+		let (payment_hash, payment_secret) = (invoice.payment_hash(), *invoice.payment_secret());
+
+		let preimage = nodes[1].node.get_payment_preimage(payment_hash, payment_secret).unwrap();
+
 		// Invoice SCIDs should always use inbound SCID aliases over the real channel ID, if one is
 		// available.
 		let chan = &nodes[1].node.list_usable_channels()[0];
@@ -707,25 +712,34 @@ mod test {
 		assert_eq!(invoice.route_hints()[0].0[0].htlc_minimum_msat, chan.inbound_htlc_minimum_msat);
 		assert_eq!(invoice.route_hints()[0].0[0].htlc_maximum_msat, chan.inbound_htlc_maximum_msat);
 
+		let custom_tlvs = RecipientCustomTlvs::new(vec![(65537, vec![42; 42])]).unwrap();
+		let optional_params = OptionalBolt11PaymentParams {
+			custom_tlvs: custom_tlvs.clone(),
+			route_params_config: RouteParametersConfig::default(),
+			retry_strategy: Retry::Attempts(0),
+		};
+
 		nodes[0]
 			.node
-			.pay_for_bolt11_invoice(
-				&invoice,
-				PaymentId([42; 32]),
-				None,
-				OptionalBolt11PaymentParams::default(),
-			)
+			.pay_for_bolt11_invoice(&invoice, PaymentId([42; 32]), None, optional_params)
 			.unwrap();
 		check_added_monitors(&nodes[0], 1);
 
 		let mut events = nodes[0].node.get_and_clear_pending_msg_events();
 		assert_eq!(events.len(), 1);
-		let payment_event = SendEvent::from_event(events.remove(0));
-		nodes[1].node.handle_update_add_htlc(node_a_id, &payment_event.msgs[0]);
-		nodes[1].node.handle_commitment_signed_batch_test(node_a_id, &payment_event.commitment_msg);
-		check_added_monitors(&nodes[1], 1);
-		let events = nodes[1].node.get_and_clear_pending_msg_events();
-		assert_eq!(events.len(), 2);
+		let ev = remove_first_msg_event_to_node(&nodes[1].node.get_our_node_id(), &mut events);
+
+		let path = &[&nodes[1]];
+		let args = PassAlongPathArgs::new(&nodes[0], path, amt_msat, payment_hash, ev)
+			.with_payment_preimage(preimage)
+			.with_payment_secret(payment_secret)
+			.with_custom_tlvs(custom_tlvs.clone().into_inner());
+
+		do_pass_along_path(args);
+		claim_payment_along_route(
+			ClaimAlongRouteArgs::new(&nodes[0], &[&[&nodes[1]]], preimage)
+				.with_custom_tlvs(custom_tlvs.into_inner()),
+		);
 	}
 
 	fn do_create_invoice_min_final_cltv_delta(with_custom_delta: bool) {