Fixing Cpp tests.
diff --git a/test/cpp/client/credentials_test.cc b/test/cpp/client/credentials_test.cc
index 743ad06..418a544 100644
--- a/test/cpp/client/credentials_test.cc
+++ b/test/cpp/client/credentials_test.cc
@@ -46,8 +46,8 @@
 };
 
 TEST_F(CredentialsTest, InvalidGoogleRefreshToken) {
-  std::shared_ptr<Credentials> bad1 = GoogleRefreshTokenCredentials("");
-  EXPECT_EQ(static_cast<Credentials*>(nullptr), bad1.get());
+  std::shared_ptr<CallCredentials> bad1 = GoogleRefreshTokenCredentials("");
+  EXPECT_EQ(static_cast<CallCredentials*>(nullptr), bad1.get());
 }
 
 }  // namespace testing