diff --git a/samples_test.go b/samples_test.go
index 9eb56b6..cf8bf78 100644
--- a/samples_test.go
+++ b/samples_test.go
@@ -1,3 +1,5 @@
+// Package draw2d_test gives test coverage with the command:
+// go test -cover ./... | grep -v "no test"
 package draw2d_test
 
 import (