tests/kafka: wait for the cluster to delete topics

Since kafka-python 2.1.0 topic deletions have become more asynchronous
so, so wait for the cluster to update its status.

Author: xrmx

tests/instrumentation/kafka_tests.py

@@ -40,7 +40,7 @@
 
 kafka = pytest.importorskip("kafka")
 
-from kafka import KafkaConsumer, KafkaProducer
+from kafka import KafkaClient, KafkaConsumer, KafkaProducer
 from kafka.admin import KafkaAdminClient, NewTopic
 
 pytestmark = [pytest.mark.kafka]
@@ -57,6 +57,13 @@ def topics():
     admin_client.create_topics([NewTopic(name, num_partitions=1, replication_factor=1) for name in topics])
     yield topics
     admin_client.delete_topics(topics)
+    client = KafkaClient(bootstrap_servers=[f"{KAFKA_HOST}:9092"])
+    try:
+        future = client.cluster.request_update()
+        client.poll(future=future)
+    except Exception as e:
+        print(e)
+        pass
 
 
 @pytest.fixture()