f - test fixups

* Explicitly assert no hanging messages after off-chain actions
* Get rid of manual user force-close for timeout
* Connect blocks on nodes[0] to make sure they don't go on-chain
* Add comment on syncing block height on nodes

Author: alecchendev

lightning/src/ln/functional_tests.rs

@@ -2237,23 +2237,27 @@ fn do_test_fail_back_before_backwards_timeout(post_fail_back_action: PostFailBac
 	create_announced_chan_between_nodes(&nodes, 0, 1);
 	let chan_2 = create_announced_chan_between_nodes(&nodes, 1, 2);
 
+	// Start every node on the same block height to make reasoning about timeouts easier
 	connect_blocks(&nodes[0], 2*CHAN_CONFIRM_DEPTH + 1 - nodes[0].best_block_info().1);
 	connect_blocks(&nodes[1], 2*CHAN_CONFIRM_DEPTH + 1 - nodes[1].best_block_info().1);
 	connect_blocks(&nodes[2], 2*CHAN_CONFIRM_DEPTH + 1 - nodes[2].best_block_info().1);
 
 	let (payment_preimage, payment_hash, _) = route_payment(&nodes[0], &[&nodes[1], &nodes[2]], 3_000_000);
 
 	// Force close downstream with timeout
-	nodes[1].node.force_close_broadcasting_latest_txn(&chan_2.2, &nodes[2].node.get_our_node_id()).unwrap();
-	check_added_monitors!(nodes[1], 1);
-	check_closed_broadcast!(nodes[1], true);
-
-	connect_blocks(&nodes[1], TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1);
+	let timeout_blocks = TEST_FINAL_CLTV + LATENCY_GRACE_PERIOD_BLOCKS + 1;
+	connect_blocks(&nodes[1], timeout_blocks);
 	let node_1_txn = test_txn_broadcast(&nodes[1], &chan_2, None, HTLCType::TIMEOUT);
-	check_closed_event(&nodes[1], 1, ClosureReason::HolderForceClosed, false);
+	check_closed_event(&nodes[1], 1, ClosureReason::CommitmentTxConfirmed, false);
+	check_closed_broadcast!(nodes[1], true);
+	check_added_monitors!(nodes[1], 1);
 
 	// Nothing is confirmed for a while
-	connect_blocks(&nodes[1], MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - TIMEOUT_FAIL_BACK_BUFFER);
+	let upstream_timeout_blocks = MIN_CLTV_EXPIRY_DELTA as u32 - LATENCY_GRACE_PERIOD_BLOCKS - TIMEOUT_FAIL_BACK_BUFFER;
+	connect_blocks(&nodes[1], upstream_timeout_blocks);
+
+	// Connect blocks for nodes[0] to make sure they don't go on-chain
+	connect_blocks(&nodes[0], timeout_blocks + upstream_timeout_blocks);
 
 	// Check that nodes[1] fails the HTLC upstream
 	expect_pending_htlcs_forwardable_and_htlc_handling_failed!(nodes[1], vec![HTLCDestination::NextHopChannel { node_id: Some(nodes[2].node.get_our_node_id()), channel_id: chan_2.2 }]);
@@ -2282,6 +2286,7 @@ fn do_test_fail_back_before_backwards_timeout(post_fail_back_action: PostFailBac
 			// Confirm nodes[1]'s claim with timeout, make sure we don't fail upstream again
 			mine_transaction(&nodes[1], &node_1_txn[0]); // Commitment
 			mine_transaction(&nodes[1], &node_1_txn[1]); // HTLC timeout
+			assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
 		},
 		PostFailBackAction::ClaimOnChain => {
 			nodes[2].node.claim_funds(payment_preimage);
@@ -2297,6 +2302,7 @@ fn do_test_fail_back_before_backwards_timeout(post_fail_back_action: PostFailBac
 
 			mine_transaction(&nodes[1], &node_2_txn[0]); // Commitment
 			mine_transaction(&nodes[1], &node_2_txn[1]); // HTLC success
+			assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
 		},
 		PostFailBackAction::FailOffChain => {
 			nodes[2].node.fail_htlc_backwards(&payment_hash);
@@ -2308,6 +2314,7 @@ fn do_test_fail_back_before_backwards_timeout(post_fail_back_action: PostFailBac
 			nodes[1].node.handle_update_fail_htlc(&nodes[2].node.get_our_node_id(), &update_fail);
 			let err_msg = get_err_msg(&nodes[1], &nodes[2].node.get_our_node_id());
 			assert_eq!(err_msg.channel_id, chan_2.2);
+			assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
 		},
 		PostFailBackAction::ClaimOffChain => {
 			nodes[2].node.claim_funds(payment_preimage);
@@ -2319,6 +2326,7 @@ fn do_test_fail_back_before_backwards_timeout(post_fail_back_action: PostFailBac
 			nodes[1].node.handle_update_fulfill_htlc(&nodes[2].node.get_our_node_id(), &update_fulfill);
 			let err_msg = get_err_msg(&nodes[1], &nodes[2].node.get_our_node_id());
 			assert_eq!(err_msg.channel_id, chan_2.2);
+			assert!(nodes[1].node.get_and_clear_pending_msg_events().is_empty());
 		},
 	};
 }