--- a/ChangeLog	Tue Dec 04 00:56:31 2018 +0100
+++ b/ChangeLog	Tue Dec 04 00:57:19 2018 +0100
@@ -1,5 +1,9 @@
 2018-12-03  Bruno Haible  <bruno@clisp.org>
 
+	linkedhash-set: Add tests.
+	* tests/test-linkedhash_set.c: New file.
+	* modules/linkedhash-set-tests: New file.
+
 	array-set: Add tests.
 	* tests/test-array_set.c: New file.
 	* modules/array-set-tests: New file.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/linkedhash-set-tests	Tue Dec 04 00:57:19 2018 +0100
@@ -0,0 +1,13 @@
+Files:
+tests/test-linkedhash_set.c
+tests/macros.h
+
+Depends-on:
+array-set
+xalloc
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-linkedhash_set
+check_PROGRAMS += test-linkedhash_set

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/test-linkedhash_set.c	Tue Dec 04 00:57:19 2018 +0100
@@ -0,0 +1,164 @@
+/* Test of set data type implementation.
+   Copyright (C) 2006-2018 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2018.
+
+   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/>.  */
+
+#include <config.h>
+
+#include "gl_linkedhash_set.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "gl_array_set.h"
+#include "xalloc.h"
+#include "macros.h"
+
+static const char *objects[30] =
+  {
+    "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o",
+    "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "<", ">", "[", "]"
+  };
+
+#define RANDOM(n) (rand () % (n))
+#define RANDOM_OBJECT() objects[RANDOM (SIZEOF (objects))]
+
+static void
+check_equals (gl_set_t set1, gl_set_t set2)
+{
+  size_t n = gl_set_size (set1);
+  const void **elements_of_set1 = XNMALLOC (n, const void *);
+  const void **elements_of_set2 = XNMALLOC (n, const void *);
+
+  gl_set_iterator_t iter1;
+  gl_set_iterator_t iter2;
+  const void *elt1;
+  const void *elt2;
+  size_t i;
+
+  iter1 = gl_set_iterator (set1);
+  iter2 = gl_set_iterator (set2);
+  for (i = 0; i < n; i++)
+    {
+      ASSERT (gl_set_iterator_next (&iter1, &elt1));
+      ASSERT (gl_set_iterator_next (&iter2, &elt2));
+      elements_of_set1[i] = elt1;
+      elements_of_set2[i] = elt2;
+    }
+  ASSERT (!gl_set_iterator_next (&iter1, &elt1));
+  ASSERT (!gl_set_iterator_next (&iter2, &elt2));
+  gl_set_iterator_free (&iter1);
+  gl_set_iterator_free (&iter2);
+
+  if (n > 0)
+    {
+      qsort (elements_of_set1, n, sizeof (const void *),
+             (int (*) (const void *, const void *)) strcmp);
+      qsort (elements_of_set2, n, sizeof (const void *),
+             (int (*) (const void *, const void *)) strcmp);
+    }
+  for (i = 0; i < n; i++)
+    ASSERT (elements_of_set1[i] == elements_of_set2[i]);
+  free (elements_of_set2);
+  free (elements_of_set1);
+}
+
+static void
+check_all (gl_set_t set1, gl_set_t set2)
+{
+  check_equals (set1, set2);
+}
+
+static bool
+string_equals (const void *elt1, const void *elt2)
+{
+  return strcmp ((const char *) elt1, (const char *) elt2) == 0;
+}
+
+static size_t
+string_hashcode (const void *elt)
+{
+  size_t hashcode = 0;
+  const char *s;
+  for (s = (const char *) elt; *s != '\0'; s++)
+    hashcode += (unsigned char) *s;
+  return hashcode;
+}
+
+int
+main (int argc, char *argv[])
+{
+  gl_set_t set1, set2;
+
+  /* Allow the user to provide a non-default random seed on the command line.  */
+  if (argc > 1)
+    srand (atoi (argv[1]));
+
+  {
+    size_t initial_size = RANDOM (20);
+    size_t i;
+    unsigned int repeat;
+
+    /* Create set1.  */
+    set1 = gl_set_nx_create_empty (GL_ARRAY_SET, string_equals, string_hashcode, NULL);
+    ASSERT (set1 != NULL);
+
+    /* Create set2.  */
+    set2 = gl_set_nx_create_empty (GL_LINKEDHASH_SET, string_equals, string_hashcode, NULL);
+    ASSERT (set2 != NULL);
+
+    check_all (set1, set2);
+
+    /* Initialize them.  */
+    for (i = 0; i < initial_size; i++)
+      {
+        const char *obj = RANDOM_OBJECT ();
+        ASSERT (gl_set_nx_add (set1, obj) == gl_set_nx_add (set2, obj));
+        check_all (set1, set2);
+      }
+
+    for (repeat = 0; repeat < 100000; repeat++)
+      {
+        unsigned int operation = RANDOM (3);
+        switch (operation)
+          {
+          case 0:
+            {
+              const char *obj = RANDOM_OBJECT ();
+              ASSERT (gl_set_search (set1, obj) == gl_set_search (set2, obj));
+            }
+            break;
+          case 1:
+            {
+              const char *obj = RANDOM_OBJECT ();
+              ASSERT (gl_set_nx_add (set1, obj) == gl_set_nx_add (set2, obj));
+            }
+            break;
+          case 2:
+            {
+              const char *obj = RANDOM_OBJECT ();
+              ASSERT (gl_set_remove (set1, obj) == gl_set_remove (set2, obj));
+            }
+            break;
+          }
+        check_all (set1, set2);
+      }
+
+    gl_set_free (set1);
+    gl_set_free (set2);
+  }
+
+  return 0;
+}