diff --git a/base/base_tests/small_set_test.cpp b/base/base_tests/small_set_test.cpp
index bb2ae235cf..41d08935d1 100644
--- a/base/base_tests/small_set_test.cpp
+++ b/base/base_tests/small_set_test.cpp
@@ -20,6 +20,8 @@ UNIT_TEST(SmallSet_Smoke)
 {
   SmallSet<300> set;
   TEST_EQUAL(set.Size(), 0, ());
+  for (uint64_t i = 0; i < 300; ++i)
+    TEST(!set.Contains(i), ());
 
   set.Insert(0);
   TEST_EQUAL(set.Size(), 1, ());