fix: use sized 1 channel

tm2/pkg/bft/consensus/common_test.go

@@ -246,14 +246,29 @@ func validatePrevoteAndPrecommit(t *testing.T, cs *ConsensusState, thisRound, lo
 }
 
 func subscribeToVoter(cs *ConsensusState, addr crypto.Address) <-chan events.Event {
-	return events.SubscribeFiltered(cs.evsw, testSubscriber, func(event events.Event) bool {
+	ch := events.SubscribeFiltered(cs.evsw, testSubscriber, func(event events.Event) bool {
 		if vote, ok := event.(types.EventVote); ok {
 			if vote.Vote.ValidatorAddress == addr {
 				return true
 			}
 		}
 		return false
 	})
+
+	// This modification addresses the deadlock issue outlined in issue
+	// #1320. By creating a buffered channel, we ensure that events are
+	// consumed even if the main thread is blocked. This prevents the
+	// deadlock that occurred when eventSwitch.FireEvent was blocked due to
+	// no available consumers for the event.
+	testch := make(chan events.Event, 1)
+	go func() {
+		defer close(testch)
+		for evt := range ch {
+			testch <- evt
+		}
+	}()
+
+	return testch
 }
 
 // -------------------------------------------------------------------------------

tm2/pkg/bft/consensus/state_test.go

@@ -3,6 +3,7 @@ package consensus
 import (
 	"bytes"
 	"fmt"
+	"reflect"
 	"testing"
 	"time"
 
@@ -1780,5 +1781,22 @@ func TestStateOutputVoteStats(t *testing.T) {
 }
 
 func subscribe(evsw events.EventSwitch, protoevent events.Event) <-chan events.Event {
-	return events.SubscribeToEvent(evsw, testSubscriber, protoevent)
+	name := reflect.ValueOf(protoevent).Type().Name()
+	listenerID := fmt.Sprintf("%s-%s", testSubscriber, name)
+	ch := events.SubscribeToEvent(evsw, listenerID, protoevent)
+
+	// Similar to the change in common_test.go, this modification introduces
+	// a buffered channel and a separate goroutine for event consumption.
+	// This approach ensures that events are consumed asynchronously,
+	// thereby avoiding the deadlock situation described in the GitHub issue
+	// where the eventSwitch.FireEvent method was blocked.
+	testch := make(chan events.Event, 1)
+	go func() {
+		defer close(testch)
+		for evt := range ch {
+			testch <- evt
+		}
+	}()
+
+	return testch
 }