diff --git a/test/cpp/client/credentials_test.cc b/test/cpp/client/credentials_test.cc
index 994d3a0fa8e..30e6dd1ca97 100644
--- a/test/cpp/client/credentials_test.cc
+++ b/test/cpp/client/credentials_test.cc
@@ -246,20 +246,26 @@ typedef void (*grpcpp_tls_on_credential_reload_done_cb)(
 
 TEST_F(CredentialsTest, TlsCredentialReloadArgCppToC) {
   TlsCredentialReloadArg arg;
-  // Only sync credential reload supported currently,
-  // so we use a nullptr call back function.
   arg.set_cb(static_cast<grpcpp_tls_on_credential_reload_done_cb>(nullptr));
   arg.set_cb_user_data(nullptr);
-  arg.set_key_materials_config(
-      static_cast<::std::shared_ptr<TlsKeyMaterialsConfig>>(nullptr));
+  ::std::shared_ptr<TlsKeyMaterialsConfig> key_materials_config;
+  struct TlsKeyMaterialsConfig::PemKeyCertPair pair1 = {"private_key1",
+                                                       "cert_chain1"};
+  struct TlsKeyMaterialsConfig::PemKeyCertPair pair2 = {"private_key2", "cert_chain2"};
+  ::std::vector<TlsKeyMaterialsConfig::PemKeyCertPair> pair_list = {pair1, pair2};
+  key_materials_config->set_key_materials("pem_root_certs", pair_list);
+  arg.set_key_materials_config(key_materials_config);
   arg.set_status(GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_NEW);
   arg.set_error_details("error_details");
   grpc_tls_credential_reload_arg* c_arg = arg.c_credential_reload_arg();
   EXPECT_EQ(c_arg->cb,
             static_cast<grpc_tls_on_credential_reload_done_cb>(nullptr));
   EXPECT_EQ(c_arg->cb_user_data, nullptr);
-  EXPECT_EQ(c_arg->key_materials_config,
-            static_cast<::std::shared_ptr<TlsKeyMaterialsConfig>>(nullptr));
+  EXPECT_EQ(c_arg->key_materials_config->pem_root_certs(), "pem_root_certs");
+  EXPECT_EQ(c_arg->key_materials_config->pem_key_cert_pair_list()[0].private_key(), "private_key1");
+  EXPECT_EQ(c_arg->key_materials_config->pem_key_cert_pair_list()[1].private_key(), "private_key2");
+  EXPECT_EQ(c_arg->key_materials_config->pem_key_cert_pair_list()[0].cert_chain(), "cert_chain1");
+  EXPECT_EQ(c_arg->key_materials_config->pem_key_cert_pair_list()[1].cert_chain(), "cert_chain2");
   EXPECT_EQ(c_arg->status, GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_NEW);
   EXPECT_STREQ(c_arg->error_details, "error_details");
 }