diff --git a/build-aux/check-mescc.sh b/build-aux/check-mescc.sh
index 16895ee2..46479a04 100755
--- a/build-aux/check-mescc.sh
+++ b/build-aux/check-mescc.sh
@@ -1,7 +1,7 @@
 #! /bin/sh
 
 # GNU Mes --- Maxwell Equations of Software
-# Copyright © 2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+# Copyright © 2017,2018,2019,2020,2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 #
 # This file is part of GNU Mes.
 #
@@ -117,6 +117,7 @@ lib/tests/scaffold/54-argv.c
 lib/tests/scaffold/55-char-array.c
 lib/tests/scaffold/60-math.c
 lib/tests/scaffold/60-math-itoa.c
+lib/tests/scaffold/60-math-modulo.c
 lib/tests/scaffold/61-array.c
 lib/tests/scaffold/62-array.c
 lib/tests/scaffold/63-struct.c
diff --git a/lib/tests/scaffold/60-math-modulo.c b/lib/tests/scaffold/60-math-modulo.c
new file mode 100644
index 00000000..05a6ea8d
--- /dev/null
+++ b/lib/tests/scaffold/60-math-modulo.c
@@ -0,0 +1,79 @@
+/* -*-comment-start: "//";comment-end:""-*-
+ * GNU Mes --- Maxwell Equations of Software
+ * Copyright © 2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
+ *
+ * This file is part of GNU Mes.
+ *
+ * GNU Mes is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * GNU Mes is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Mes.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <mes/lib.h>
+
+int
+main ()
+{
+  int i;
+
+  oputs ("\n");
+
+  oputs ("t: 1 % 2\n");
+  i = 1 % 2;
+  if (i != 1)
+    return 1;
+
+  oputs ("t: 2 % 4\n");
+  i = 2 % 4;
+  if (i != 2)
+    return 2;
+
+  oputs ("t: 3 % 4\n");
+  i = 3 % 4;
+  if (i != 3)
+    return 3;
+
+  oputs ("t: 1 % 256\n");
+  i = 1 % 256;
+  if (i != 1)
+    return 4;
+
+  unsigned u;
+
+  oputs ("\n");
+
+  oputs ("t: 1U % 2\n");
+  u = 1 % 2;
+  if (u != 1)
+    return 5;
+
+  oputs ("t: 2U % 4\n");
+  u = 2 % 4;
+  if (u != 2)
+    return 6;
+
+  oputs ("t: 3U % 4\n");
+  u = 3 % 4;
+  if (u != 3)
+    return 7;
+
+  oputs ("t: 1U % 256\n");
+  u = 1 % 256;
+  if (u != 1)
+    return 8;
+
+  return 0;
+}