diff --git a/tests/conftest.py b/tests/conftest.py
index 15f9243312c..d4379b422de 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2081,6 +2081,8 @@ def disable_block_async_io() -> Generator[None]:
     calls.clear()
 
 
+# Ensure that incorrectly formatted mac addresses are rejected during
+# DhcpServiceInfo initialisation
 _real_dhcp_service_info_init = DhcpServiceInfo.__init__