add multithreaded test

tests/integration/test_zookeeper_config/test.py

@@ -1,6 +1,7 @@
 
 
 import time
+import threading
 from os import path as p, unlink
 from tempfile import NamedTemporaryFile
 
@@ -174,6 +175,17 @@ def test_secure_connection():
         assert node1.query("SELECT count() FROM system.zookeeper WHERE path = '/'") == '2\n'
         assert node2.query("SELECT count() FROM system.zookeeper WHERE path = '/'") == '2\n'
 
+
+        kThreadsNumber = 16
+        kIterations = 100
+        threads = []
+        for _ in range(kThreadsNumber):
+            threads.append(threading.Thread(target=(lambda: 
+                [node1.query("SELECT count() FROM system.zookeeper WHERE path = '/'") for _ in range(kIterations)])))
+
+        for thread in threads:
+            thread.join()
+
     finally:
         cluster.shutdown()
         unlink(docker_compose.name)