diff --git a/test/unit/radix_tree_t.c b/test/unit/radix_tree_t.c
index ea033c7d2..6b4494455 100644
--- a/test/unit/radix_tree_t.c
+++ b/test/unit/radix_tree_t.c
@@ -1,5 +1,5 @@
 // Copyright (C) 2018 Red Hat, Inc. All rights reserved.
-// 
+//
 // This file is part of LVM2.
 //
 // This copyrighted material is made available to anyone wishing to use,
@@ -9,7 +9,7 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with this program; if not, write to the Free Software Foundation,
 // Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- 
+
 #include "units.h"
 #include "base/data-struct/radix-tree.h"
 #include "base/memory/container_of.h"
@@ -348,7 +348,7 @@ static void test_remove_prefix(void *fixture)
 
 	T_ASSERT(radix_tree_is_well_formed(rt));
 
-	// remove keys in a sub range 
+	// remove keys in a sub range
 	k[0] = 21;
 	T_ASSERT_EQUAL(radix_tree_remove_prefix(rt, k, 1), count);
 	T_ASSERT(radix_tree_is_well_formed(rt));
@@ -542,7 +542,7 @@ static void test_remove_calls_dtr(void *fixture)
 		}
 
 		T_ASSERT(radix_tree_is_well_formed(rt));
-		
+
 		// double check
 		for (i = 0; i < DTR_COUNT; i++) {
 			uint8_t *k = keys + (i * 3);
@@ -597,7 +597,7 @@ static void test_destroy_calls_dtr(void *fixture)
 
 		T_ASSERT(radix_tree_is_well_formed(rt));
 	}
-		
+
 	radix_tree_destroy(rt);
 	T_ASSERT(c.c == DTR_COUNT);
 	for (i = 0; i < DTR_COUNT; i++)
@@ -810,6 +810,37 @@ static void test_bcache_scenario3(void *fixture)
 	#include "test/unit/rt_case1.c"
 }
 
+static bool _uniq_visit(struct radix_tree_iterator *it,
+			const void *key, size_t keylen, union radix_value v)
+{
+	struct visitor *vt = container_of(it, struct visitor, it);
+	T_ASSERT_EQUAL(v.n, 2); // always expecting value == 2
+	vt->count++;
+	return true;
+}
+
+static void test_uniq_insert(void *fixture)
+{
+	struct radix_tree *rt = fixture;
+	struct visitor vt = { .it.visit = _uniq_visit };
+	uint8_t k[6] = "test1";
+	uint8_t l[6] = "test2";
+	union radix_value v1 = { .n = 1 };
+	union radix_value v2 = { .n = 2 };
+
+	T_ASSERT(radix_tree_insert(rt, k, sizeof(k), v1));
+	T_ASSERT(radix_tree_insert(rt, k, sizeof(k), v1));
+	T_ASSERT_EQUAL(radix_tree_uniq_insert(rt, k, sizeof(k), v2), -1);
+
+	T_ASSERT(radix_tree_uniq_insert(rt, l, sizeof(l), v1));
+	T_ASSERT_EQUAL(radix_tree_uniq_insert(rt, l, sizeof(l), v2), -1);
+
+	T_ASSERT(radix_tree_is_well_formed(rt));
+
+	radix_tree_iterate(rt, NULL, 0, &vt.it);
+	T_ASSERT_EQUAL(radix_tree_size(rt), vt.count);
+}
+
 //----------------------------------------------------------------
 #define T(path, desc, fn) register_test(ts, "/base/data-struct/radix-tree/" path, desc, fn)
 
@@ -846,6 +877,7 @@ void radix_tree_tests(struct dm_list *all_tests)
 	T("bcache-scenario", "A specific series of keys from a bcache scenario", test_bcache_scenario);
 	T("bcache-scenario-2", "A second series of keys from a bcache scenario", test_bcache_scenario2);
 	T("bcache-scenario-3", "A third series of keys from a bcache scenario", test_bcache_scenario3);
+	T("uniq-insert", "Test insert with test for uniq key", test_uniq_insert);
 
 	dm_list_add(all_tests, &ts->list);
 }