diff --git a/tests/gpgscm/scheme.c b/tests/gpgscm/scheme.c
index 0453754a6..b2ff72145 100644
--- a/tests/gpgscm/scheme.c
+++ b/tests/gpgscm/scheme.c
@@ -1735,6 +1735,9 @@ port_clear_location (scheme *sc, port *p)
 static void
 port_increment_current_line (scheme *sc, port *p, long delta)
 {
+  if (delta == 0)
+    return;
+
   p->curr_line =
     mk_integer(sc, ivalue_unchecked(p->curr_line) + delta);
 }