fixup test GC

Author: BourgoisMickael

extensions/gc/GarbageCollectorProducer.js

@@ -30,8 +30,16 @@ class GarbageCollectorProducer {
             requiredAcks: this._kafkaConfig.requiredAcks,
             topic: this._topic,
         });
-        producer.once('error', () => {});
+        producer.once('error', err => {
+            this._log.error('error from GarbageCollectorProducer backbeat producer', {
+                topic: this._topic,
+                error: err,
+                errmsg: err.toString(),
+            });
+            cb(err);
+        });
         producer.once('ready', () => {
+            this._log.info('GarbageCollectorProducer backbeat producer ready');
             producer.removeAllListeners('error');
             producer.on('error', err =>
                 this._log.error('error from backbeat producer', {