diff --git a/notify_systemd_test.go b/notify_systemd_test.go
index 4c85b27..7e31c0a 100644
--- a/notify_systemd_test.go
+++ b/notify_systemd_test.go
@@ -1,6 +1,8 @@
 //go:build systemd
 
-// testing messages to systemd
+// Testing messages to systemd.
+// For this test to work, use `NOTIFY_SOCKET=/run/systemd/notify go test -tags systemd -test.run 'TestSystemdNotify(.*)' -v`
+// Note that the socket path is for Ubuntu Linux; other systems may use different specifications.
 
 package main