Bugfix jaeger exporter test panic

CHANGELOG.md

@@ -96,6 +96,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - BatchSpanProcessor now drops span batches that failed to be exported. (#1860)
 - Use `http://localhost:14268/api/traces` as default Jaeger collector endpoint instead of `http://localhost:14250`. (#1898)
 - Allow trailing and leading whitespace in the parsing of a `tracestate` header. (#1931)
+- Add logic to determine if the channel is closed to fix Jaeger exporter test panic with close closed channel. (#1870, #1973)
 
 ### Security
 

exporters/trace/jaeger/reconnecting_udp_client_test.go

@@ -97,7 +97,9 @@ func assertConnWritable(t *testing.T, conn udpConn, serverConn net.PacketConn) {
 func waitForCallWithTimeout(call *mock.Call) bool {
 	called := make(chan struct{})
 	call.Run(func(args mock.Arguments) {
-		close(called)
+		if !isChannelClosed(called) {
+			close(called)
+		}
 	})
 
 	var wasCalled bool
@@ -114,6 +116,15 @@ func waitForCallWithTimeout(call *mock.Call) bool {
 	return wasCalled
 }
 
+func isChannelClosed(ch <-chan struct{}) bool {
+	select {
+	case <-ch:
+		return true
+	default:
+	}
+	return false
+}
+
 func waitForConnCondition(conn *reconnectingUDPConn, condition func(conn *reconnectingUDPConn) bool) bool {
 	var conditionVal bool
 	for i := 0; i < 10; i++ {