Increase heartbeat interval in debug builds

When running in debug mode, the timeout was getting triggered during the
contract setup phase.

daemon/src/lib.rs

@@ -52,7 +52,12 @@ pub mod wallet;
 pub mod wallet_sync;
 pub mod wire;
 
-pub const HEARTBEAT_INTERVAL: std::time::Duration = Duration::from_secs(5);
+// Certain operations (e.g. contract setup) take long time in debug mode,
+// causing us to lag behind in processing heartbeats.
+// Increasing the value for debug mode makes sure that we don't cause problems
+// when testing / CI, whilst the release can still detect status faster
+pub const HEARTBEAT_INTERVAL: std::time::Duration =
+    Duration::from_secs(if cfg!(debug_assertions) { 30 } else { 5 });
 
 pub const N_PAYOUTS: usize = 200;