stdc_memreverse8: Add tests.

* tests/test-stdc_memreverse8.c: New file.
* modules/stdc_memreverse8-tests: New file.

ChangeLog

@@ -1,5 +1,9 @@
 2026-03-15  Bruno Haible  <bruno@clisp.org>
 
+	stdc_memreverse8: Add tests.
+	* tests/test-stdc_memreverse8.c: New file.
+	* modules/stdc_memreverse8-tests: New file.
+
 	stdc_memreverse8: New module.
 	* lib/stdbit.in.h: Include <stddef.h>.
 	(_GL_STDC_MEMREVERSE8_INLINE): New macro.

modules/stdc_memreverse8-tests

@@ -0,0 +1,11 @@
+Files:
+tests/test-stdc_memreverse8.c
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-stdc_memreverse8
+check_PROGRAMS += test-stdc_memreverse8

tests/test-stdc_memreverse8.c

@@ -0,0 +1,77 @@
+/* Test of stdc_memreverse8 function.
+   Copyright (C) 2026 Free Software Foundation, Inc.
+
+   This program 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.
+
+   This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2026.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdbit.h>
+
+#include "macros.h"
+
+static unsigned char data[10] =
+  { 0x12, 0x31, 0x47, 0xBF, 0xC4, 0xD3, 0xEE, 0xF1, 0x90, 0x44 };
+
+static unsigned char *volatile ptr;
+
+int
+main (void)
+{
+  ptr = data;
+
+  stdc_memreverse8 (0, ptr + 5);
+  /* Expect: 0x12, 0x31, 0x47, 0xBF, 0xC4, 0xD3, 0xEE, 0xF1, 0x90, 0x44  */
+  ASSERT (ptr[4] == 0xC4);
+  ASSERT (ptr[5] == 0xD3);
+
+  stdc_memreverse8 (1, ptr + 5);
+  /* Expect: 0x12, 0x31, 0x47, 0xBF, 0xC4, 0xD3, 0xEE, 0xF1, 0x90, 0x44  */
+  ASSERT (ptr[4] == 0xC4);
+  ASSERT (ptr[5] == 0xD3);
+  ASSERT (ptr[6] == 0xEE);
+
+  stdc_memreverse8 (2, ptr + 5);
+  /* Expect: 0x12, 0x31, 0x47, 0xBF, 0xC4, 0xEE, 0xD3, 0xF1, 0x90, 0x44  */
+  ASSERT (ptr[4] == 0xC4);
+  ASSERT (ptr[5] == 0xEE);
+  ASSERT (ptr[6] == 0xD3);
+  ASSERT (ptr[7] == 0xF1);
+
+  stdc_memreverse8 (4, ptr + 3);
+  /* Expect: 0x12, 0x31, 0x47, 0xD3, 0xEE, 0xC4, 0xBF, 0xF1, 0x90, 0x44  */
+  ASSERT (ptr[2] == 0x47);
+  ASSERT (ptr[3] == 0xD3);
+  ASSERT (ptr[4] == 0xEE);
+  ASSERT (ptr[5] == 0xC4);
+  ASSERT (ptr[6] == 0xBF);
+  ASSERT (ptr[7] == 0xF1);
+
+  stdc_memreverse8 (8, ptr + 1);
+  /* Expect: 0x12, 0x90, 0xF1, 0xBF, 0xC4, 0xEE, 0xD3, 0x47, 0x31, 0x44  */
+  ASSERT (ptr[0] == 0x12);
+  ASSERT (ptr[1] == 0x90);
+  ASSERT (ptr[2] == 0xF1);
+  ASSERT (ptr[3] == 0xBF);
+  ASSERT (ptr[4] == 0xC4);
+  ASSERT (ptr[5] == 0xEE);
+  ASSERT (ptr[6] == 0xD3);
+  ASSERT (ptr[7] == 0x47);
+  ASSERT (ptr[8] == 0x31);
+  ASSERT (ptr[9] == 0x44);
+
+  return test_exit_status;
+}