tProxy: time out silent upstream setup responses

[GitGab19]

Proof of Concept

diff --git a/miner-apps/translator/src/lib/sv2/upstream/mod.rs b/miner-apps/translator/src/lib/sv2/upstream/mod.rs
--- a/miner-apps/translator/src/lib/sv2/upstream/mod.rs
+++ b/miner-apps/translator/src/lib/sv2/upstream/mod.rs
@@ -577,3 +577,56 @@ impl Upstream {
         })
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use async_channel::unbounded;
+    use std::{sync::Arc, time::Duration};
+
+    #[tokio::test]
+    async fn silent_upstream_does_not_hold_setup_forever() {
+        let (upstream_sender, upstream_outbound_receiver) = unbounded::<Sv2Frame>();
+        let (_upstream_inbound_sender, upstream_receiver) = unbounded::<Sv2Frame>();
+        let (channel_manager_sender, _channel_manager_receiver) = unbounded::<Sv2Frame>();
+        let (_channel_manager_sender, channel_manager_input_receiver) =
+            unbounded::<Sv2Frame>();
+
+        let upstream = Upstream {
+            upstream_io: UpstreamIo::new(
+                upstream_receiver,
+                upstream_sender,
+                channel_manager_sender,
+                channel_manager_input_receiver,
+            ),
+            required_extensions: vec![],
+            address: "127.0.0.1:1234".parse().unwrap(),
+        };
+
+        let cancellation_token = CancellationToken::new();
+        let fallback_coordinator = FallbackCoordinator::new();
+        let task_manager = Arc::new(TaskManager::new());
+        let start_task = tokio::spawn(upstream.start(
+            cancellation_token.clone(),
+            fallback_coordinator,
+            task_manager,
+        ));
+
+        tokio::time::timeout(Duration::from_secs(1), upstream_outbound_receiver.recv())
+            .await
+            .expect("translator never sent SetupConnection")
+            .expect("translator outbound channel closed before SetupConnection");
+
+        tokio::time::sleep(Duration::from_secs(12)).await;
+        let setup_timed_out = start_task.is_finished();
+
+        if !setup_timed_out {
+            cancellation_token.cancel();
+        }
+        let _ = tokio::time::timeout(Duration::from_secs(1), start_task).await;
+
+        assert!(
+            setup_timed_out,
+            "translator kept waiting forever for a silent upstream SetupConnection response"
+        );
+    }
+}