diff --git a/bin/tests/system/hooks/tests_async_plugin.py b/bin/tests/system/hooks/tests_async_plugin.py
index 48f9feefbd..2f42e27379 100644
--- a/bin/tests/system/hooks/tests_async_plugin.py
+++ b/bin/tests/system/hooks/tests_async_plugin.py
@@ -23,4 +23,5 @@ def test_async_hook(named_port):
         "A",
     )
     ans = dns.query.udp(msg, "10.53.0.1", timeout=10, port=named_port)
+    # the test-async plugin changes the status of any positive answer to NOTIMP
     assert ans.rcode() == dns.rcode.NOTIMP