diff --git a/tests/simple_test.sh b/tests/simple_test.sh
index 99ebbc5..c744a34 100755
--- a/tests/simple_test.sh
+++ b/tests/simple_test.sh
@@ -41,4 +41,5 @@ fi
 ################################################################################
 rm -f  test4* ref check
 
+# for Jenkins CI platform, we need an exit code: PASS (0) vs. FAILED (1)
 exit $RETVAL