--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2010-01-09  Bruno Haible  <bruno@clisp.org>
 
+	Tests for module 'unistr/u16-check'.
+	* modules/unistr/u16-check-tests: New file.
+	* tests/unistr/test-u16-check.c: New file.
+
 	Tests for module 'unistr/u8-check'.
 	* modules/unistr/u8-check-tests: New file.
 	* tests/unistr/test-u8-check.c: New file.

new file mode 100644
--- /dev/null
+++ b/modules/unistr/u16-check-tests
@@ -0,0 +1,12 @@
+Files:
+tests/unistr/test-u16-check.c
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-u16-check
+check_PROGRAMS += test-u16-check
+test_u16_check_SOURCES = unistr/test-u16-check.c

new file mode 100644
--- /dev/null
+++ b/tests/unistr/test-u16-check.c
@@ -0,0 +1,66 @@
+/* Test of u16_check() 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 "macros.h"
+
+int
+main ()
+{
+  /* Test empty string.  */
+  {
+    static const uint16_t input[] = { 0 };
+    ASSERT (u16_check (input, 0) == NULL);
+  }
+
+  /* Test valid non-empty string.  */
+  {
+    static const uint16_t input[] = /* "Данило Шеган" */
+      { 0x0414, 0x0430, 0x043D, 0x0438, 0x043B, 0x043E, 0x0020, 0x0428, 0x0435, 0x0433, 0x0430, 0x043D };
+    ASSERT (u16_check (input, SIZEOF (input)) == NULL);
+  }
+
+  /* Test out-of-range character with 2 units: U+110000.  */
+  {
+    static const uint16_t input[] = { 0x0414, 0x0430, 0xDBFF, 0xE000 };
+    ASSERT (u16_check (input, SIZEOF (input)) == input + 2);
+  }
+
+  /* Test surrogate codepoints.  */
+  {
+    static const uint16_t input[] = { 0x0414, 0x0430, 0xDBFF, 0xDFFF };
+    ASSERT (u16_check (input, SIZEOF (input)) == NULL);
+  }
+  {
+    static const uint16_t input[] = { 0x0414, 0x0430, 0xDBFF };
+    ASSERT (u16_check (input, SIZEOF (input)) == input + 2);
+  }
+  {
+    static const uint16_t input[] = { 0x0414, 0x0430, 0xDFFF };
+    ASSERT (u16_check (input, SIZEOF (input)) == input + 2);
+  }
+  {
+    static const uint16_t input[] = { 0x0414, 0x0430, 0xDFFF, 0xDBFF };
+    ASSERT (u16_check (input, SIZEOF (input)) == input + 2);
+  }
+
+  return 0;
+}