introduce util/digest/city_ut.cpp

ref:2bd6e26cda5245c96d0b2f3c326dd13e0827c326

util/digest/city.cpp

@@ -310,14 +310,4 @@ uint128 CityHash128(const char* s, size_t len) noexcept {
     }
 }
 
-// TODO(yazevnul): move this function to unittests
-void TestCompilationOfCityHashTemplates() {
-    TStringBuf s;
-    CityHash64(s);
-    CityHash64WithSeed(s, 1);
-    CityHash64WithSeeds(s, 1, 2);
-    CityHash128(s);
-    CityHash128WithSeed(s, uint128(1, 2));
-}
-
 #endif

util/digest/city_ut.cpp

@@ -0,0 +1,15 @@
+#include "city.h"
+
+#include <library/cpp/testing/unittest/registar.h>
+
+Y_UNIT_TEST_SUITE(TCityTest) {
+    Y_UNIT_TEST(TestTemplatesCompiling) {
+        TStringBuf s;
+        CityHash64(s);
+        CityHash64WithSeed(s, 1);
+        CityHash64WithSeeds(s, 1, 2);
+        CityHash128(s);
+        CityHash128WithSeed(s, uint128(1, 2));
+        UNIT_ASSERT(s.empty());
+    }
+};

util/digest/ut/ya.make

@@ -4,9 +4,10 @@ OWNER(g:util)
 SUBSCRIBER(g:util-subscribers)
 
 SRCS(
+    digest/city_ut.cpp
     digest/fnv_ut.cpp
-    digest/murmur_ut.cpp
     digest/multi_ut.cpp
+    digest/murmur_ut.cpp
     digest/sequence_ut.cpp
 )