tests: add warning "For development purpose only."

Signed-off-by: Karel Zak <kzak@redhat.com>
diff --git a/tests/run.sh b/tests/run.sh
index 795df90..7b66239 100755
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -20,6 +20,9 @@
 echo
 echo "------------------ Utils-linux-ng regression tests ------------------"
 echo
+echo "                    For development purpose only.                    "
+echo "                 Don't execute on production system!                 "
+echo
 
 rm -f *~