diff --git a/tests/test-mcore.c b/tests/test-mcore.c
index 5430c2d8..65f71083 100644
--- a/tests/test-mcore.c
+++ b/tests/test-mcore.c
@@ -193,6 +193,8 @@ static void test_test(void)
   assert(!M_PARENTHESIS_P(a()));
   assert(!M_PARENTHESIS_P(a(ada)));
   assert(!M_PARENTHESIS_P(a,b));
+  assert(!M_PARENTHESIS_P(a));
+  assert(!M_PARENTHESIS_P());
 }