Close bad connection as notified by Heartbeat in P2P code

[MitchTurner]

Context

During poll our heartbeat::Handler previously would count failed connection and close the connection after a set number of failures.

            if self.failure_count >= self.config.max_failures.into() {
                // Request from `Swarm` to close the faulty connection
                return Poll::Ready(ConnectionHandlerEvent::Close(
                    HeartbeatFailure::Timeout,
                ))
            }

They have since removed the ability for handlers to close connections: libp2p/rust-libp2p#4755

We still want bad connections to be closed and reopened, so we need a new solution.

Requirements

• Write a test that shows when connections with a peer fail more than the max_failures, it closes the connection.
• Implement code to pass that test 👍

[AurelienFT]

@MitchTurner Is it ok if the test just test that the handler send a notification to disconnect or we want ot test it at service level ? Because I'm having difficulties testing this at service level.

[MitchTurner]

It might be the case that I was being overly prescriptive. It reads like typical TDD propaganda :). You have the context now to decide the best means of testing it, whether that is keeping the current arch or refactoring to a more testible design.

[AurelienFT]

I always prefer to get with test first too and I prefer testing it at service level but I don't find a way to make the failure_count increase in tests at service level. There is too much process going on etc... so I wll propably end up doing it at handler level even if it's not my preference.