Merge branch 'master' of github.com:grpc/grpc into cpp_auth_md_processor

14 files changed, 230 insertions, 84 deletions

diff --git a/test/cpp/common/auth_property_iterator_test.cc b/test/cpp/common/auth_property_iterator_test.cc
index 630c38c7f6..e6226d6a09 100644
--- a/test/cpp/common/auth_property_iterator_test.cc
+++ b/test/cpp/common/auth_property_iterator_test.cc
@@ -35,11 +35,14 @@
 #include <grpc++/support/auth_context.h>
 #include <gtest/gtest.h>
 #include "src/cpp/common/secure_auth_context.h"
+#include "test/cpp/util/string_ref_helper.h"
 
 extern "C" {
 #include "src/core/security/security_context.h"
 }
 
+using ::grpc::testing::ToString;
+
 namespace grpc {
 namespace {
 
@@ -84,12 +87,12 @@ TEST_F(AuthPropertyIteratorTest, GeneralTest) {
   AuthProperty p1 = *iter;
   iter++;
   AuthProperty p2 = *iter;
-  EXPECT_EQ("name", p0.first);
-  EXPECT_EQ("chapi", p0.second);
-  EXPECT_EQ("name", p1.first);
-  EXPECT_EQ("chapo", p1.second);
-  EXPECT_EQ("foo", p2.first);
-  EXPECT_EQ("bar", p2.second);
+  EXPECT_EQ("name", ToString(p0.first));
+  EXPECT_EQ("chapi", ToString(p0.second));
+  EXPECT_EQ("name", ToString(p1.first));
+  EXPECT_EQ("chapo", ToString(p1.second));
+  EXPECT_EQ("foo", ToString(p2.first));
+  EXPECT_EQ("bar", ToString(p2.second));
   ++iter;
   EXPECT_EQ(empty_iter, iter);
 }
diff --git a/test/cpp/common/secure_auth_context_test.cc b/test/cpp/common/secure_auth_context_test.cc
index e1f6bf05ce..4ab7fcacdf 100644
--- a/test/cpp/common/secure_auth_context_test.cc
+++ b/test/cpp/common/secure_auth_context_test.cc
@@ -35,11 +35,14 @@
 #include <grpc++/support/auth_context.h>
 #include <gtest/gtest.h>
 #include "src/cpp/common/secure_auth_context.h"
+#include "test/cpp/util/string_ref_helper.h"
 
 extern "C" {
 #include "src/core/security/security_context.h"
 }
 
+using grpc::testing::ToString;
+
 namespace grpc {
 namespace {
 
@@ -63,14 +66,14 @@ TEST_F(SecureAuthContextTest, Properties) {
   context.AddProperty("foo", "bar");
   EXPECT_TRUE(context.SetPeerIdentityPropertyName("name"));
 
-  std::vector<grpc::string> peer_identity = context.GetPeerIdentity();
+  std::vector<grpc::string_ref> peer_identity = context.GetPeerIdentity();
   EXPECT_EQ(2u, peer_identity.size());
-  EXPECT_EQ("chapi", peer_identity[0]);
-  EXPECT_EQ("chapo", peer_identity[1]);
+  EXPECT_EQ("chapi", ToString(peer_identity[0]));
+  EXPECT_EQ("chapo", ToString(peer_identity[1]));
   EXPECT_EQ("name", context.GetPeerIdentityPropertyName());
-  std::vector<grpc::string> bar = context.FindPropertyValues("foo");
+  std::vector<grpc::string_ref> bar = context.FindPropertyValues("foo");
   EXPECT_EQ(1u, bar.size());
-  EXPECT_EQ("bar", bar[0]);
+  EXPECT_EQ("bar", ToString(bar[0]));
 }
 
 TEST_F(SecureAuthContextTest, Iterators) {
@@ -88,12 +91,12 @@ TEST_F(SecureAuthContextTest, Iterators) {
   AuthProperty p1 = *iter;
   iter++;
   AuthProperty p2 = *iter;
-  EXPECT_EQ("name", p0.first);
-  EXPECT_EQ("chapi", p0.second);
-  EXPECT_EQ("name", p1.first);
-  EXPECT_EQ("chapo", p1.second);
-  EXPECT_EQ("foo", p2.first);
-  EXPECT_EQ("bar", p2.second);
+  EXPECT_EQ("name", ToString(p0.first));
+  EXPECT_EQ("chapi", ToString(p0.second));
+  EXPECT_EQ("name", ToString(p1.first));
+  EXPECT_EQ("chapo", ToString(p1.second));
+  EXPECT_EQ("foo", ToString(p2.first));
+  EXPECT_EQ("bar", ToString(p2.second));
   ++iter;
   EXPECT_EQ(context.end(), iter);
 }
diff --git a/test/cpp/end2end/async_end2end_test.cc b/test/cpp/end2end/async_end2end_test.cc
index 6343810ee9..41b91e459b 100644
--- a/test/cpp/end2end/async_end2end_test.cc
+++ b/test/cpp/end2end/async_end2end_test.cc
@@ -50,6 +50,7 @@
 #include "test/core/util/test_config.h"
 #include "test/cpp/util/echo_duplicate.grpc.pb.h"
 #include "test/cpp/util/echo.grpc.pb.h"
+#include "test/cpp/util/string_ref_helper.h"
 
 #ifdef GPR_POSIX_SOCKET
 #include "src/core/iomgr/pollset_posix.h"
@@ -484,8 +485,10 @@ TEST_P(AsyncEnd2endTest, ClientInitialMetadataRpc) {
   Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
   EXPECT_EQ(send_request.message(), recv_request.message());
   auto client_initial_metadata = srv_ctx.client_metadata();
-  EXPECT_EQ(meta1.second, client_initial_metadata.find(meta1.first)->second);
-  EXPECT_EQ(meta2.second, client_initial_metadata.find(meta2.first)->second);
+  EXPECT_EQ(meta1.second,
+            ToString(client_initial_metadata.find(meta1.first)->second));
+  EXPECT_EQ(meta2.second,
+            ToString(client_initial_metadata.find(meta2.first)->second));
   EXPECT_GE(client_initial_metadata.size(), static_cast<size_t>(2));
 
   send_response.set_message(recv_request.message());
@@ -532,8 +535,10 @@ TEST_P(AsyncEnd2endTest, ServerInitialMetadataRpc) {
   response_reader->ReadInitialMetadata(tag(4));
   Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
   auto server_initial_metadata = cli_ctx.GetServerInitialMetadata();
-  EXPECT_EQ(meta1.second, server_initial_metadata.find(meta1.first)->second);
-  EXPECT_EQ(meta2.second, server_initial_metadata.find(meta2.first)->second);
+  EXPECT_EQ(meta1.second,
+            ToString(server_initial_metadata.find(meta1.first)->second));
+  EXPECT_EQ(meta2.second,
+            ToString(server_initial_metadata.find(meta2.first)->second));
   EXPECT_EQ(static_cast<size_t>(2), server_initial_metadata.size());
 
   send_response.set_message(recv_request.message());
@@ -586,8 +591,10 @@ TEST_P(AsyncEnd2endTest, ServerTrailingMetadataRpc) {
   EXPECT_EQ(send_response.message(), recv_response.message());
   EXPECT_TRUE(recv_status.ok());
   auto server_trailing_metadata = cli_ctx.GetServerTrailingMetadata();
-  EXPECT_EQ(meta1.second, server_trailing_metadata.find(meta1.first)->second);
-  EXPECT_EQ(meta2.second, server_trailing_metadata.find(meta2.first)->second);
+  EXPECT_EQ(meta1.second,
+            ToString(server_trailing_metadata.find(meta1.first)->second));
+  EXPECT_EQ(meta2.second,
+            ToString(server_trailing_metadata.find(meta2.first)->second));
   EXPECT_EQ(static_cast<size_t>(2), server_trailing_metadata.size());
 }
 
@@ -631,8 +638,10 @@ TEST_P(AsyncEnd2endTest, MetadataRpc) {
   Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
   EXPECT_EQ(send_request.message(), recv_request.message());
   auto client_initial_metadata = srv_ctx.client_metadata();
-  EXPECT_EQ(meta1.second, client_initial_metadata.find(meta1.first)->second);
-  EXPECT_EQ(meta2.second, client_initial_metadata.find(meta2.first)->second);
+  EXPECT_EQ(meta1.second,
+            ToString(client_initial_metadata.find(meta1.first)->second));
+  EXPECT_EQ(meta2.second,
+            ToString(client_initial_metadata.find(meta2.first)->second));
   EXPECT_GE(client_initial_metadata.size(), static_cast<size_t>(2));
 
   srv_ctx.AddInitialMetadata(meta3.first, meta3.second);
@@ -642,8 +651,10 @@ TEST_P(AsyncEnd2endTest, MetadataRpc) {
   response_reader->ReadInitialMetadata(tag(4));
   Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
   auto server_initial_metadata = cli_ctx.GetServerInitialMetadata();
-  EXPECT_EQ(meta3.second, server_initial_metadata.find(meta3.first)->second);
-  EXPECT_EQ(meta4.second, server_initial_metadata.find(meta4.first)->second);
+  EXPECT_EQ(meta3.second,
+            ToString(server_initial_metadata.find(meta3.first)->second));
+  EXPECT_EQ(meta4.second,
+            ToString(server_initial_metadata.find(meta4.first)->second));
   EXPECT_GE(server_initial_metadata.size(), static_cast<size_t>(2));
 
   send_response.set_message(recv_request.message());
@@ -658,8 +669,10 @@ TEST_P(AsyncEnd2endTest, MetadataRpc) {
   EXPECT_EQ(send_response.message(), recv_response.message());
   EXPECT_TRUE(recv_status.ok());
   auto server_trailing_metadata = cli_ctx.GetServerTrailingMetadata();
-  EXPECT_EQ(meta5.second, server_trailing_metadata.find(meta5.first)->second);
-  EXPECT_EQ(meta6.second, server_trailing_metadata.find(meta6.first)->second);
+  EXPECT_EQ(meta5.second,
+            ToString(server_trailing_metadata.find(meta5.first)->second));
+  EXPECT_EQ(meta6.second,
+            ToString(server_trailing_metadata.find(meta6.first)->second));
   EXPECT_GE(server_trailing_metadata.size(), static_cast<size_t>(2));
 }
 
diff --git a/test/cpp/end2end/end2end_test.cc b/test/cpp/end2end/end2end_test.cc
index 2728dce07e..9826837c60 100644
--- a/test/cpp/end2end/end2end_test.cc
+++ b/test/cpp/end2end/end2end_test.cc
@@ -53,6 +53,7 @@
 #include "test/core/util/test_config.h"
 #include "test/cpp/util/echo_duplicate.grpc.pb.h"
 #include "test/cpp/util/echo.grpc.pb.h"
+#include "test/cpp/util/string_ref_helper.h"
 
 using grpc::cpp::test::util::EchoRequest;
 using grpc::cpp::test::util::EchoResponse;
@@ -80,10 +81,10 @@ void MaybeEchoDeadline(ServerContext* context, const EchoRequest* request,
 
 void CheckServerAuthContext(const ServerContext* context) {
   std::shared_ptr<const AuthContext> auth_ctx = context->auth_context();
-  std::vector<grpc::string> ssl =
+  std::vector<grpc::string_ref> ssl =
       auth_ctx->FindPropertyValues("transport_security_type");
   EXPECT_EQ(1u, ssl.size());
-  EXPECT_EQ("ssl", ssl[0]);
+  EXPECT_EQ("ssl", ToString(ssl[0]));
   EXPECT_TRUE(auth_ctx->GetPeerIdentityPropertyName().empty());
   EXPECT_TRUE(auth_ctx->GetPeerIdentity().empty());
 }
@@ -152,12 +153,13 @@ class TestServiceImpl : public ::grpc::cpp::test::util::TestService::Service {
     }
 
     if (request->has_param() && request->param().echo_metadata()) {
-      const std::multimap<grpc::string, grpc::string>& client_metadata =
+      const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata =
           context->client_metadata();
-      for (std::multimap<grpc::string, grpc::string>::const_iterator iter =
-               client_metadata.begin();
+      for (std::multimap<grpc::string_ref, grpc::string_ref>::const_iterator
+               iter = client_metadata.begin();
            iter != client_metadata.end(); ++iter) {
-        context->AddTrailingMetadata((*iter).first, (*iter).second);
+        context->AddTrailingMetadata(ToString(iter->first),
+                                     ToString(iter->second));
       }
     }
     if (request->has_param() && request->param().check_auth_context()) {
@@ -182,12 +184,12 @@ class TestServiceImpl : public ::grpc::cpp::test::util::TestService::Service {
     EchoRequest request;
     response->set_message("");
     int cancel_after_reads = 0;
-    const std::multimap<grpc::string, grpc::string> client_initial_metadata =
-        context->client_metadata();
+    const std::multimap<grpc::string_ref, grpc::string_ref>&
+        client_initial_metadata = context->client_metadata();
     if (client_initial_metadata.find(kServerCancelAfterReads) !=
         client_initial_metadata.end()) {
-      std::istringstream iss(
-          client_initial_metadata.find(kServerCancelAfterReads)->second);
+      std::istringstream iss(ToString(
+          client_initial_metadata.find(kServerCancelAfterReads)->second));
       iss >> cancel_after_reads;
       gpr_log(GPR_INFO, "cancel_after_reads %d", cancel_after_reads);
     }
@@ -721,14 +723,15 @@ TEST_F(End2endTest, RpcMaxMessageSize) {
   EXPECT_FALSE(s.ok());
 }
 
-bool MetadataContains(const std::multimap<grpc::string, grpc::string>& metadata,
-                      const grpc::string& key, const grpc::string& value) {
+bool MetadataContains(
+    const std::multimap<grpc::string_ref, grpc::string_ref>& metadata,
+    const grpc::string& key, const grpc::string& value) {
   int count = 0;
 
-  for (std::multimap<grpc::string, grpc::string>::const_iterator iter =
+  for (std::multimap<grpc::string_ref, grpc::string_ref>::const_iterator iter =
            metadata.begin();
        iter != metadata.end(); ++iter) {
-    if ((*iter).first == key && (*iter).second == value) {
+    if (ToString(iter->first) == key && ToString(iter->second) == value) {
       count++;
     }
   }
@@ -837,16 +840,17 @@ TEST_F(End2endTest, ClientAuthContext) {
   EXPECT_TRUE(s.ok());
 
   std::shared_ptr<const AuthContext> auth_ctx = context.auth_context();
-  std::vector<grpc::string> ssl =
+  std::vector<grpc::string_ref> ssl =
       auth_ctx->FindPropertyValues("transport_security_type");
   EXPECT_EQ(1u, ssl.size());
-  EXPECT_EQ("ssl", ssl[0]);
+  EXPECT_EQ("ssl", ToString(ssl[0]));
   EXPECT_EQ("x509_subject_alternative_name",
             auth_ctx->GetPeerIdentityPropertyName());
   EXPECT_EQ(3u, auth_ctx->GetPeerIdentity().size());
-  EXPECT_EQ("*.test.google.fr", auth_ctx->GetPeerIdentity()[0]);
-  EXPECT_EQ("waterzooi.test.google.be", auth_ctx->GetPeerIdentity()[1]);
-  EXPECT_EQ("*.test.youtube.com", auth_ctx->GetPeerIdentity()[2]);
+  EXPECT_EQ("*.test.google.fr", ToString(auth_ctx->GetPeerIdentity()[0]));
+  EXPECT_EQ("waterzooi.test.google.be",
+            ToString(auth_ctx->GetPeerIdentity()[1]));
+  EXPECT_EQ("*.test.youtube.com", ToString(auth_ctx->GetPeerIdentity()[2]));
 }
 
 // Make the response larger than the flow control window.
diff --git a/test/cpp/end2end/generic_end2end_test.cc b/test/cpp/end2end/generic_end2end_test.cc
index de7eab8dc2..809eef058c 100644
--- a/test/cpp/end2end/generic_end2end_test.cc
+++ b/test/cpp/end2end/generic_end2end_test.cc
@@ -160,7 +160,7 @@ class GenericEnd2endTest : public ::testing::Test {
                                    srv_cq_.get(), tag(4));
 
       verify_ok(srv_cq_.get(), 4, true);
-      EXPECT_EQ(server_host_, srv_ctx.host());
+      EXPECT_EQ(server_host_, srv_ctx.host().substr(0, server_host_.length()));
       EXPECT_EQ(kMethodName, srv_ctx.method());
       ByteBuffer recv_buffer;
       stream.Read(&recv_buffer, tag(5));
@@ -233,7 +233,7 @@ TEST_F(GenericEnd2endTest, SimpleBidiStreaming) {
                                srv_cq_.get(), tag(2));
 
   verify_ok(srv_cq_.get(), 2, true);
-  EXPECT_EQ(server_host_, srv_ctx.host());
+  EXPECT_EQ(server_host_, srv_ctx.host().substr(0, server_host_.length()));
   EXPECT_EQ(kMethodName, srv_ctx.method());
 
   std::unique_ptr<ByteBuffer> send_buffer =
diff --git a/test/cpp/interop/interop_client.cc b/test/cpp/interop/interop_client.cc
index fa358585d4..ca13cdc53d 100644
--- a/test/cpp/interop/interop_client.cc
+++ b/test/cpp/interop/interop_client.cc
@@ -362,20 +362,37 @@ void InteropClient::DoResponseCompressedStreaming() {
       request.set_response_type(payload_types[i]);
       request.set_response_compression(compression_types[j]);
 
-      for (unsigned int i = 0; i < response_stream_sizes.size(); ++i) {
+      for (size_t k = 0; k < response_stream_sizes.size(); ++k) {
         ResponseParameters* response_parameter =
             request.add_response_parameters();
-        response_parameter->set_size(response_stream_sizes[i]);
+        response_parameter->set_size(response_stream_sizes[k]);
       }
       StreamingOutputCallResponse response;
 
       std::unique_ptr<ClientReader<StreamingOutputCallResponse>> stream(
           stub->StreamingOutputCall(&context, request));
 
-      unsigned int i = 0;
+      size_t k = 0;
       while (stream->Read(&response)) {
-        GPR_ASSERT(response.payload().body() ==
-                   grpc::string(response_stream_sizes[i], '\0'));
+        // Payload related checks.
+        if (request.response_type() != PayloadType::RANDOM) {
+          GPR_ASSERT(response.payload().type() == request.response_type());
+        }
+        switch (response.payload().type()) {
+          case PayloadType::COMPRESSABLE:
+            GPR_ASSERT(response.payload().body() ==
+                       grpc::string(response_stream_sizes[k], '\0'));
+            break;
+          case PayloadType::UNCOMPRESSABLE: {
+            std::ifstream rnd_file(kRandomFile);
+            GPR_ASSERT(rnd_file.good());
+            for (int n = 0; n < response_stream_sizes[k]; n++) {
+              GPR_ASSERT(response.payload().body()[n] == (char)rnd_file.get());
+            }
+          } break;
+          default:
+            GPR_ASSERT(false);
+        }
 
         // Compression related checks.
         GPR_ASSERT(request.response_compression() ==
@@ -391,10 +408,10 @@ void InteropClient::DoResponseCompressedStreaming() {
                      GRPC_WRITE_INTERNAL_COMPRESS);
         }
 
-        ++i;
+        ++k;
       }
 
-      GPR_ASSERT(response_stream_sizes.size() == i);
+      GPR_ASSERT(response_stream_sizes.size() == k);
       Status s = stream->Finish();
 
       AssertOkOrPrintErrorStatus(s);
diff --git a/test/cpp/interop/server.cc b/test/cpp/interop/server.cc
index 35ec890aa0..4921fde9fa 100644
--- a/test/cpp/interop/server.cc
+++ b/test/cpp/interop/server.cc
@@ -158,11 +158,13 @@ class TestServiceImpl : public TestService::Service {
     SetResponseCompression(context, *request);
     StreamingOutputCallResponse response;
     bool write_success = true;
-    response.mutable_payload()->set_type(request->response_type());
     for (int i = 0; write_success && i < request->response_parameters_size();
          i++) {
-      response.mutable_payload()->set_body(
-          grpc::string(request->response_parameters(i).size(), '\0'));
+      if (!SetPayload(request->response_type(),
+                      request->response_parameters(i).size(),
+                      response.mutable_payload())) {
+        return Status(grpc::StatusCode::INTERNAL, "Error creating payload.");
+      }
       write_success = writer->Write(response);
     }
     if (write_success) {
diff --git a/test/cpp/util/cli_call.cc b/test/cpp/util/cli_call.cc
index d60cee9c02..9a769848a4 100644
--- a/test/cpp/util/cli_call.cc
+++ b/test/cpp/util/cli_call.cc
@@ -51,14 +51,14 @@ void* tag(int i) { return (void*)(gpr_intptr)i; }
 
 Status CliCall::Call(std::shared_ptr<grpc::Channel> channel,
                      const grpc::string& method, const grpc::string& request,
-                     grpc::string* response, const MetadataContainer& metadata,
-                     MetadataContainer* server_initial_metadata,
-                     MetadataContainer* server_trailing_metadata) {
+                     grpc::string* response,
+                     const OutgoingMetadataContainer& metadata,
+                     IncomingMetadataContainer* server_initial_metadata,
+                     IncomingMetadataContainer* server_trailing_metadata) {
   std::unique_ptr<grpc::GenericStub> stub(new grpc::GenericStub(channel));
   grpc::ClientContext ctx;
   if (!metadata.empty()) {
-    for (std::multimap<grpc::string, grpc::string>::const_iterator iter =
-             metadata.begin();
+    for (OutgoingMetadataContainer::const_iterator iter = metadata.begin();
          iter != metadata.end(); ++iter) {
       ctx.AddMetadata(iter->first, iter->second);
     }
diff --git a/test/cpp/util/cli_call.h b/test/cpp/util/cli_call.h
index 7a3dcf2e9f..2fbc9618b6 100644
--- a/test/cpp/util/cli_call.h
+++ b/test/cpp/util/cli_call.h
@@ -38,18 +38,22 @@
 
 #include <grpc++/channel.h>
 #include <grpc++/support/status.h>
+#include <grpc++/support/string_ref.h>
 
 namespace grpc {
 namespace testing {
 
 class CliCall GRPC_FINAL {
  public:
-  typedef std::multimap<grpc::string, grpc::string> MetadataContainer;
+  typedef std::multimap<grpc::string, grpc::string> OutgoingMetadataContainer;
+  typedef std::multimap<grpc::string_ref, grpc::string_ref>
+      IncomingMetadataContainer;
   static Status Call(std::shared_ptr<grpc::Channel> channel,
                      const grpc::string& method, const grpc::string& request,
-                     grpc::string* response, const MetadataContainer& metadata,
-                     MetadataContainer* server_initial_metadata,
-                     MetadataContainer* server_trailing_metadata);
+                     grpc::string* response,
+                     const OutgoingMetadataContainer& metadata,
+                     IncomingMetadataContainer* server_initial_metadata,
+                     IncomingMetadataContainer* server_trailing_metadata);
 };
 
 }  // namespace testing
diff --git a/test/cpp/util/cli_call_test.cc b/test/cpp/util/cli_call_test.cc
index 35bfad202f..111a0e9f76 100644
--- a/test/cpp/util/cli_call_test.cc
+++ b/test/cpp/util/cli_call_test.cc
@@ -47,6 +47,7 @@
 #include "test/core/util/port.h"
 #include "test/core/util/test_config.h"
 #include "test/cpp/util/echo.grpc.pb.h"
+#include "test/cpp/util/string_ref_helper.h"
 
 using grpc::cpp::test::util::EchoRequest;
 using grpc::cpp::test::util::EchoResponse;
@@ -59,10 +60,11 @@ class TestServiceImpl : public ::grpc::cpp::test::util::TestService::Service {
   Status Echo(ServerContext* context, const EchoRequest* request,
               EchoResponse* response) GRPC_OVERRIDE {
     if (!context->client_metadata().empty()) {
-      for (std::multimap<grpc::string, grpc::string>::const_iterator iter =
-               context->client_metadata().begin();
+      for (std::multimap<grpc::string_ref, grpc::string_ref>::const_iterator
+               iter = context->client_metadata().begin();
            iter != context->client_metadata().end(); ++iter) {
-        context->AddInitialMetadata(iter->first, iter->second);
+        context->AddInitialMetadata(ToString(iter->first),
+                                    ToString(iter->second));
       }
     }
     context->AddTrailingMetadata("trailing_key", "trailing_value");
@@ -119,8 +121,9 @@ TEST_F(CliCallTest, SimpleRpc) {
   grpc::string request_bin, response_bin, expected_response_bin;
   EXPECT_TRUE(request.SerializeToString(&request_bin));
   EXPECT_TRUE(response.SerializeToString(&expected_response_bin));
-  std::multimap<grpc::string, grpc::string> client_metadata,
-      server_initial_metadata, server_trailing_metadata;
+  std::multimap<grpc::string, grpc::string> client_metadata;
+  std::multimap<grpc::string_ref, grpc::string_ref> server_initial_metadata,
+      server_trailing_metadata;
   client_metadata.insert(std::pair<grpc::string, grpc::string>("key1", "val1"));
   Status s2 = CliCall::Call(channel_, kMethod, request_bin, &response_bin,
                             client_metadata, &server_initial_metadata,
diff --git a/test/cpp/util/grpc_cli.cc b/test/cpp/util/grpc_cli.cc
index 746d67deeb..a4888efebe 100644
--- a/test/cpp/util/grpc_cli.cc
+++ b/test/cpp/util/grpc_cli.cc
@@ -68,8 +68,10 @@
 #include <grpc++/channel.h>
 #include <grpc++/create_channel.h>
 #include <grpc++/credentials.h>
+#include <grpc++/support/string_ref.h>
 
 #include "test/cpp/util/cli_call.h"
+#include "test/cpp/util/string_ref_helper.h"
 #include "test/cpp/util/test_config.h"
 
 DEFINE_bool(enable_ssl, true, "Whether to use ssl/tls.");
@@ -104,16 +106,19 @@ void ParseMetadataFlag(
   }
 }
 
-void PrintMetadata(const std::multimap<grpc::string, grpc::string>& m,
-                   const grpc::string& message) {
+template <typename T>
+void PrintMetadata(const T& m, const grpc::string& message) {
   if (m.empty()) {
     return;
   }
   std::cout << message << std::endl;
-  for (std::multimap<grpc::string, grpc::string>::const_iterator iter =
-           m.begin();
-       iter != m.end(); ++iter) {
-    std::cout << iter->first << " : " << iter->second << std::endl;
+  grpc::string pair;
+  for (typename T::const_iterator iter = m.begin(); iter != m.end(); ++iter) {
+    pair.clear();
+    pair.append(iter->first.data(), iter->first.size());
+    pair.append(" : ");
+    pair.append(iter->second.data(), iter->second.size());
+    std::cout << pair << std::endl;
   }
 }
 
@@ -157,8 +162,9 @@ int main(int argc, char** argv) {
       grpc::CreateChannel(server_address, creds, grpc::ChannelArguments());
 
   grpc::string response;
-  std::multimap<grpc::string, grpc::string> client_metadata,
-      server_initial_metadata, server_trailing_metadata;
+  std::multimap<grpc::string, grpc::string> client_metadata;
+  std::multimap<grpc::string_ref, grpc::string_ref> server_initial_metadata,
+      server_trailing_metadata;
   ParseMetadataFlag(&client_metadata);
   PrintMetadata(client_metadata, "Sending client initial metadata:");
   grpc::Status s = grpc::testing::CliCall::Call(
diff --git a/test/cpp/util/string_ref_helper.cc b/test/cpp/util/string_ref_helper.cc
new file mode 100644
index 0000000000..4eb4fe0357
--- /dev/null
+++ b/test/cpp/util/string_ref_helper.cc
@@ -0,0 +1,44 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "test/cpp/util/string_ref_helper.h"
+
+namespace grpc {
+namespace testing {
+
+grpc::string ToString(const grpc::string_ref& r) {
+  return grpc::string(r.data(), r.size());
+}
+
+}  // namespace testing
+}  // namespace grpc
diff --git a/test/cpp/util/string_ref_helper.h b/test/cpp/util/string_ref_helper.h
new file mode 100644
index 0000000000..ac94bcd018
--- /dev/null
+++ b/test/cpp/util/string_ref_helper.h
@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_TEST_CPP_UTIL_STRING_REF_HELPER_H
+#define GRPC_TEST_CPP_UTIL_STRING_REF_HELPER_H
+
+#include <grpc++/support/string_ref.h>
+
+namespace grpc {
+namespace testing {
+
+grpc::string ToString(const grpc::string_ref& r);
+
+}  // namespace testing
+}  // namespace grpc
+
+#endif  // GRPC_TEST_CPP_UTIL_STRING_REF_HELPER_H
diff --git a/test/cpp/util/string_ref_test.cc b/test/cpp/util/string_ref_test.cc
index c4ca4fce84..465072d43e 100644
--- a/test/cpp/util/string_ref_test.cc
+++ b/test/cpp/util/string_ref_test.cc
@@ -100,8 +100,8 @@ TEST_F(StringRefTest, Assignment) {
 TEST_F(StringRefTest, Iterator) {
   string_ref s(kTestString);
   size_t i = 0;
-  for (char c : s) {
-    EXPECT_EQ(kTestString[i++], c);
+  for (auto it = s.cbegin(); it != s.cend(); ++it) {
+    EXPECT_EQ(kTestString[i++], *it);
   }
   EXPECT_EQ(strlen(kTestString), i);
 }