diff --git a/format-test.cc b/format-test.cc
index ecc2ff4f..e3557249 100644
--- a/format-test.cc
+++ b/format-test.cc
@@ -233,14 +233,14 @@ TEST(UtilTest, CountDigits) {
 #ifdef _WIN32
 TEST(UtilTest, UTF16ToUTF8) {
   std::string s = "ёжик";
-  UTF16ToUTF8 u(L"\x0451\x0436\x0438\x043A");
+  fmt::internal::UTF16ToUTF8 u(L"\x0451\x0436\x0438\x043A");
   EXPECT_EQ(s, str(u));
   EXPECT_EQ(s.size(), u.size());
 }
 
 TEST(UtilTest, UTF8ToUTF16) {
   std::string s = "лошадка";
-  UTF8ToUTF16 u(s.c_str());
+  fmt::internal::UTF8ToUTF16 u(s.c_str());
   EXPECT_EQ(L"\x043B\x043E\x0448\x0430\x0434\x043A\x0430", str(u));
   EXPECT_EQ(7, u.size());
 }