diff --git a/tests/tango/test_tango_transport.py b/tests/tango/test_tango_transport.py
index 56387d3ef1..45825b25e4 100644
--- a/tests/tango/test_tango_transport.py
+++ b/tests/tango/test_tango_transport.py
@@ -463,6 +463,9 @@ def callback(reading):
         await asyncio.sleep(0.5)
         assert val == "new label"
 
+    assert attr_proxy._poll_task
+    attr_proxy.unsubscribe_callback()
+
 
 # --------------------------------------------------------------------
 @pytest.mark.asyncio
@@ -479,6 +482,7 @@ def callback(reading, value):
     attr_proxy.subscribe_callback(callback)
     await asyncio.sleep(0.2)
     assert "Could not poll the attribute" in str(attr_proxy.exception)
+    attr_proxy.unsubscribe_callback()
 
 
 # --------------------------------------------------------------------