diff --git a/t/unit/backends/test_asynchronous.py b/t/unit/backends/test_asynchronous.py
index c0fe894900..6593cd53e5 100644
--- a/t/unit/backends/test_asynchronous.py
+++ b/t/unit/backends/test_asynchronous.py
@@ -158,7 +158,10 @@ def sleep(self):
 
     def result_consumer_drain_events(self, timeout=None):
         import eventlet
-        eventlet.sleep(0)
+        # `drain_events` of asynchronous backends with pubsub have to sleep
+        # while waiting events for not more then `interval` timeout,
+        # but events may coming sooner
+        eventlet.sleep(timeout/10)
 
     def schedule_thread(self, thread):
         import eventlet
@@ -204,7 +207,10 @@ def sleep(self):
 
     def result_consumer_drain_events(self, timeout=None):
         import gevent
-        gevent.sleep(0)
+        # `drain_events` of asynchronous backends with pubsub have to sleep
+        # while waiting events for not more then `interval` timeout,
+        # but events may coming sooner
+        gevent.sleep(timeout/10)
 
     def schedule_thread(self, thread):
         import gevent