Use signal for handling ChannelPending in test_background_event_handling

This fixes two potential panics within the test if the
`BackgroundProcessor` for `nodes[0]` consumed the `ChannelPending` event
prior to us consuming it manually in `end_open_channel`. The first panic
would happen within the event handler, since `ChannelPending` was not
being handled. The second panic would happen upon expecting the
`ChannelPending` event after handling `nodes[1]`'s `funding_signed` if
the `BackgroundProcessor` handled the event first. To ensure we still
reliably receive a `ChannelPending` event once possible, we let the
`BackgroundProcessor` consume the event and notify it.

diff --git a/lightning-background-processor/src/lib.rs b/lightning-background-processor/src/lib.rs
index a45dc6d6c74c1b548afc516b0e482bafa9946a66..21e9d419471ee6cc5fb619a0480642600096513c 100644 (file)
--- a/lightning-background-processor/src/lib.rs
+++ b/lightning-background-processor/src/lib.rs
@@ -1057,7 +1057,11 @@ mod tests {
                        let events = $node_a.node.get_and_clear_pending_events();
                        assert_eq!(events.len(), 1);
                        let (temporary_channel_id, tx) = handle_funding_generation_ready!(events[0], $channel_value);
-                       end_open_channel!($node_a, $node_b, temporary_channel_id, tx);
+                       $node_a.node.funding_transaction_generated(&temporary_channel_id, &$node_b.node.get_our_node_id(), tx.clone()).unwrap();
+                       $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+                       get_event!($node_b, Event::ChannelPending);
+                       $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+                       get_event!($node_a, Event::ChannelPending);
                        tx
                }}
        }
@@ -1087,17 +1091,6 @@ mod tests {
                }}
        }
 
-       macro_rules! end_open_channel {
-               ($node_a: expr, $node_b: expr, $temporary_channel_id: expr, $tx: expr) => {{
-                       $node_a.node.funding_transaction_generated(&$temporary_channel_id, &$node_b.node.get_our_node_id(), $tx.clone()).unwrap();
-                       $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
-                       get_event!($node_b, Event::ChannelPending);
-
-                       $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
-                       get_event!($node_a, Event::ChannelPending);
-               }}
-       }
-
        fn confirm_transaction_depth(node: &mut Node, tx: &Transaction, depth: u32) {
                for i in 1..=depth {
                        let prev_blockhash = node.best_block.block_hash();
@@ -1310,9 +1303,11 @@ mod tests {
                let persister = Arc::new(Persister::new(data_dir.clone()));
 
                // Set up a background event handler for FundingGenerationReady events.
-               let (sender, receiver) = std::sync::mpsc::sync_channel(1);
+               let (funding_generation_send, funding_generation_recv) = std::sync::mpsc::sync_channel(1);
+               let (channel_pending_send, channel_pending_recv) = std::sync::mpsc::sync_channel(1);
                let event_handler = move |event: Event| match event {
-                       Event::FundingGenerationReady { .. } => sender.send(handle_funding_generation_ready!(event, channel_value)).unwrap(),
+                       Event::FundingGenerationReady { .. } => funding_generation_send.send(handle_funding_generation_ready!(event, channel_value)).unwrap(),
+                       Event::ChannelPending { .. } => channel_pending_send.send(()).unwrap(),
                        Event::ChannelReady { .. } => {},
                        _ => panic!("Unexpected event: {:?}", event),
                };
@@ -1321,10 +1316,15 @@ mod tests {
 
                // Open a channel and check that the FundingGenerationReady event was handled.
                begin_open_channel!(nodes[0], nodes[1], channel_value);
-               let (temporary_channel_id, funding_tx) = receiver
+               let (temporary_channel_id, funding_tx) = funding_generation_recv
                        .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
                        .expect("FundingGenerationReady not handled within deadline");
-               end_open_channel!(nodes[0], nodes[1], temporary_channel_id, funding_tx);
+               nodes[0].node.funding_transaction_generated(&temporary_channel_id, &nodes[1].node.get_our_node_id(), funding_tx.clone()).unwrap();
+               nodes[1].node.handle_funding_created(&nodes[0].node.get_our_node_id(), &get_event_msg!(nodes[0], MessageSendEvent::SendFundingCreated, nodes[1].node.get_our_node_id()));
+               get_event!(nodes[1], Event::ChannelPending);
+               nodes[0].node.handle_funding_signed(&nodes[1].node.get_our_node_id(), &get_event_msg!(nodes[1], MessageSendEvent::SendFundingSigned, nodes[0].node.get_our_node_id()));
+               let _ = channel_pending_recv.recv_timeout(Duration::from_secs(EVENT_DEADLINE))
+                       .expect("ChannelPending not handled within deadline");
 
                // Confirm the funding transaction.
                confirm_transaction(&mut nodes[0], &funding_tx);