--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2010-01-10  Bruno Haible  <bruno@clisp.org>
 
+	Tests for module 'unistr/u8-cmp'.
+	* modules/unistr/u8-cmp-tests: New file.
+	* tests/unistr/test-u8-cmp.c: New file.
+	* tests/unistr/test-cmp.h: New file, based on tests/test-memcmp.c.
+
 	Tests for module 'unistr/u32-set'.
 	* modules/unistr/u32-set-tests: New file.
 	* tests/unistr/test-u32-set.c: New file.

new file mode 100644
--- /dev/null
+++ b/modules/unistr/u8-cmp-tests
@@ -0,0 +1,20 @@
+Files:
+tests/unistr/test-u8-cmp.c
+tests/unistr/test-cmp.h
+tests/zerosize-ptr.h
+tests/macros.h
+m4/mmap-anon.m4
+
+Depends-on:
+extensions
+getpagesize
+
+configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_HEADERS_ONCE([sys/mman.h])
+AC_CHECK_FUNCS_ONCE([mprotect])
+
+Makefile.am:
+TESTS += test-u8-cmp
+check_PROGRAMS += test-u8-cmp
+test_u8_cmp_SOURCES = unistr/test-u8-cmp.c

new file mode 100644
--- /dev/null
+++ b/tests/unistr/test-cmp.h
@@ -0,0 +1,97 @@
+/* Test of uN_cmp() functions.
+   Copyright (C) 2008-2010 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 <http://www.gnu.org/licenses/>.  */
+
+/* Written by Simon Josefsson and Bruno Haible <bruno@clisp.org>, 2010.  */
+
+static void
+test_cmp (void)
+{
+  /* Test equal / not equal distinction.  */
+  ASSERT (U_CMP (zerosize_ptr (), zerosize_ptr (), 0) == 0);
+  {
+    static const UNIT input1[] = { 'f', 'o', 'o', 0 };
+    static const UNIT input2[] = { 'f', 'o', 'o', 'b', 'a', 'r', 0 };
+    ASSERT (U_CMP (input1, input2, 2) == 0);
+    ASSERT (U_CMP (input1, input2, 3) == 0);
+    ASSERT (U_CMP (input1, input2, 4) != 0);
+  }
+  {
+    static const UNIT input1[] = { 'f', 'o', 'o', 0 };
+    static const UNIT input2[] = { 'b', 'a', 'r', 0 };
+    ASSERT (U_CMP (input1, input2, 1) != 0);
+    ASSERT (U_CMP (input1, input2, 3) != 0);
+  }
+
+  /* Test less / equal / greater distinction.  */
+  {
+    static const UNIT input1[] = { 'f', 'o', 'o', 0 };
+    static const UNIT input2[] = { 'm', 'o', 'o', 0 };
+    ASSERT (U_CMP (input1, input2, 4) < 0);
+    ASSERT (U_CMP (input2, input1, 4) > 0);
+  }
+  {
+    static const UNIT input1[] = { 'o', 'o', 'm', 'p', 'h', 0 };
+    static const UNIT input2[] = { 'o', 'o', 'p', 's', 0 };
+    ASSERT (U_CMP (input1, input2, 3) < 0);
+    ASSERT (U_CMP (input2, input1, 3) > 0);
+  }
+  {
+    static const UNIT input1[] = { 'f', 'o', 'o', 0 };
+    static const UNIT input2[] = { 'f', 'o', 'o', 'b', 'a', 'r', 0 };
+    ASSERT (U_CMP (input1, input2, 4) < 0);
+    ASSERT (U_CMP (input2, input1, 4) > 0);
+  }
+
+  /* Some old versions of memcmp were not 8-bit clean.  */
+  {
+    static const UNIT input1[] = { 0x40 };
+    static const UNIT input2[] = { 0xC2 };
+    ASSERT (U_CMP (input1, input2, 1) < 0);
+    ASSERT (U_CMP (input2, input1, 1) > 0);
+  }
+  {
+    static const UNIT input1[] = { 0xC2 };
+    static const UNIT input2[] = { 0xC3 };
+    ASSERT (U_CMP (input1, input2, 1) < 0);
+    ASSERT (U_CMP (input2, input1, 1) > 0);
+  }
+
+  /* The Next x86 OpenStep bug shows up only when comparing 16 bytes
+     or more and with at least one buffer not starting on a 4-byte boundary.
+     William Lewis provided this test program.   */
+  {
+    UNIT foo[21];
+    UNIT bar[21];
+    int i;
+    for (i = 0; i < 4; i++)
+      {
+        UNIT *a = foo + i;
+        UNIT *b = bar + i;
+        int j;
+        for (j = 0; j < 8; j++)
+          a[j] = '-';
+        a[8] = '0';
+        for (j = 9; j < 16; j++)
+          a[j] = '1';
+        for (j = 0; j < 8; j++)
+          b[j] = '-';
+        b[8] = '1';
+        for (j = 9; j < 16; j++)
+          b[j] = '0';
+        ASSERT (U_CMP (a, b, 16) < 0);
+      }
+  }
+}

new file mode 100644
--- /dev/null
+++ b/tests/unistr/test-u8-cmp.c
@@ -0,0 +1,45 @@
+/* Test of u8_cmp() function.
+   Copyright (C) 2010 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 <http://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2010.  */
+
+#include <config.h>
+
+#include "unistr.h"
+
+#include "zerosize-ptr.h"
+#include "macros.h"
+
+#define UNIT uint8_t
+#define U_CMP u8_cmp
+#define MAGIC 0xBA
+#include "test-cmp.h"
+
+int
+main ()
+{
+  test_cmp ();
+
+  /* Test comparison with non-BMP characters.  */
+  {
+    static const UNIT input1[] = { 0xF0, 0x9D, 0x94, 0x9E };
+    static const UNIT input2[] = { 0xEF, 0xBB, 0xBF, 0x00 };
+    ASSERT (U_CMP (input1, input2, 4) > 0);
+    ASSERT (U_CMP (input2, input1, 4) < 0);
+  }
+
+  return 0;
+}