/*
 *
 * Copyright 2018 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <memory>
#include <vector>

#include <grpcpp/channel.h>
#include <grpcpp/client_context.h>
#include <grpcpp/create_channel.h>
#include <grpcpp/generic/generic_stub.h>
#include <grpcpp/impl/codegen/client_interceptor.h>
#include <grpcpp/impl/codegen/proto_utils.h>
#include <grpcpp/server.h>
#include <grpcpp/server_builder.h>
#include <grpcpp/server_context.h>

#include "src/proto/grpc/testing/echo.grpc.pb.h"
#include "test/core/util/port.h"
#include "test/core/util/test_config.h"
#include "test/cpp/end2end/test_service_impl.h"
#include "test/cpp/util/byte_buffer_proto_helper.h"
#include "test/cpp/util/string_ref_helper.h"

#include <gtest/gtest.h>

namespace grpc {
namespace testing {
namespace {

class EchoTestServiceStreamingImpl : public EchoTestService::Service {
 public:
  ~EchoTestServiceStreamingImpl() override {}

  Status BidiStream(
      ServerContext* context,
      grpc::ServerReaderWriter<EchoResponse, EchoRequest>* stream) override {
    EchoRequest req;
    EchoResponse resp;
    auto client_metadata = context->client_metadata();
    for (const auto& pair : client_metadata) {
      context->AddTrailingMetadata(ToString(pair.first), ToString(pair.second));
    }

    while (stream->Read(&req)) {
      resp.set_message(req.message());
      stream->Write(resp, grpc::WriteOptions());
    }
    return Status::OK;
  }
};

class ClientInterceptorsStreamingEnd2EndTest : public ::testing::Test {
 protected:
  ClientInterceptorsStreamingEnd2EndTest() {
    int port = grpc_pick_unused_port_or_die();

    ServerBuilder builder;
    server_address_ = "localhost:" + std::to_string(port);
    builder.AddListeningPort(server_address_, InsecureServerCredentials());
    builder.RegisterService(&service_);
    server_ = builder.BuildAndStart();
  }
  std::string server_address_;
  EchoTestServiceStreamingImpl service_;
  std::unique_ptr<Server> server_;
};

class ClientInterceptorsEnd2endTest : public ::testing::Test {
 protected:
  ClientInterceptorsEnd2endTest() {
    int port = grpc_pick_unused_port_or_die();

    ServerBuilder builder;
    server_address_ = "localhost:" + std::to_string(port);
    builder.AddListeningPort(server_address_, InsecureServerCredentials());
    builder.RegisterService(&service_);
    server_ = builder.BuildAndStart();
  }

  ~ClientInterceptorsEnd2endTest() { server_->Shutdown(); }

  std::string server_address_;
  TestServiceImpl service_;
  std::unique_ptr<Server> server_;
};

/* This interceptor does nothing. Just keeps a global count on the number of
 * times it was invoked. */
class DummyInterceptor : public experimental::Interceptor {
 public:
  DummyInterceptor(experimental::ClientRpcInfo* info) {}

  virtual void Intercept(experimental::InterceptorBatchMethods* methods) {
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_INITIAL_METADATA)) {
      num_times_run_++;
    } else if (methods->QueryInterceptionHookPoint(
                   experimental::InterceptionHookPoints::
                       POST_RECV_INITIAL_METADATA)) {
      num_times_run_reverse_++;
    }
    methods->Proceed();
  }

  static void Reset() {
    num_times_run_.store(0);
    num_times_run_reverse_.store(0);
  }

  static int GetNumTimesRun() {
    EXPECT_EQ(num_times_run_.load(), num_times_run_reverse_.load());
    return num_times_run_.load();
  }

 private:
  static std::atomic<int> num_times_run_;
  static std::atomic<int> num_times_run_reverse_;
};

std::atomic<int> DummyInterceptor::num_times_run_;
std::atomic<int> DummyInterceptor::num_times_run_reverse_;

class DummyInterceptorFactory
    : public experimental::ClientInterceptorFactoryInterface {
 public:
  virtual experimental::Interceptor* CreateClientInterceptor(
      experimental::ClientRpcInfo* info) override {
    return new DummyInterceptor(info);
  }
};

/* Hijacks Echo RPC and fills in the expected values */
class HijackingInterceptor : public experimental::Interceptor {
 public:
  HijackingInterceptor(experimental::ClientRpcInfo* info) {
    info_ = info;
    // Make sure it is the right method
    EXPECT_EQ(strcmp("/grpc.testing.EchoTestService/Echo", info->method()), 0);
  }

  virtual void Intercept(experimental::InterceptorBatchMethods* methods) {
    // gpr_log(GPR_ERROR, "ran this");
    bool hijack = false;
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_INITIAL_METADATA)) {
      auto* map = methods->GetSendInitialMetadata();
      // Check that we can see the test metadata
      ASSERT_EQ(map->size(), static_cast<unsigned>(1));
      auto iterator = map->begin();
      EXPECT_EQ("testkey", iterator->first);
      EXPECT_EQ("testvalue", iterator->second);
      hijack = true;
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_MESSAGE)) {
      EchoRequest req;
      auto* buffer = methods->GetSendMessage();
      auto copied_buffer = *buffer;
      SerializationTraits<EchoRequest>::Deserialize(&copied_buffer, &req);
      EXPECT_EQ(req.message(), "Hello");
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_CLOSE)) {
      // Got nothing to do here for now
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_INITIAL_METADATA)) {
      auto* map = methods->GetRecvInitialMetadata();
      // Got nothing better to do here for now
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_MESSAGE)) {
      EchoResponse* resp =
          static_cast<EchoResponse*>(methods->GetRecvMessage());
      // Check that we got the hijacked message, and re-insert the expected
      // message
      EXPECT_EQ(resp->message(), "Hello1");
      resp->set_message("Hello");
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_STATUS)) {
      auto* map = methods->GetRecvTrailingMetadata();
      bool found = false;
      // Check that we received the metadata as an echo
      for (const auto& pair : *map) {
        found = pair.first.starts_with("testkey") &&
                pair.second.starts_with("testvalue");
        if (found) break;
      }
      EXPECT_EQ(found, true);
      auto* status = methods->GetRecvStatus();
      EXPECT_EQ(status->ok(), true);
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_INITIAL_METADATA)) {
      auto* map = methods->GetRecvInitialMetadata();
      // Got nothing better to do here at the moment
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_MESSAGE)) {
      // Insert a different message than expected
      EchoResponse* resp =
          static_cast<EchoResponse*>(methods->GetRecvMessage());
      resp->set_message("Hello1");
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_STATUS)) {
      auto* map = methods->GetRecvTrailingMetadata();
      // insert the metadata that we want
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
      map->insert(std::make_pair("testkey", "testvalue"));
      auto* status = methods->GetRecvStatus();
      *status = Status(StatusCode::OK, "");
    }
    if (hijack) {
      methods->Hijack();
    } else {
      methods->Proceed();
    }
  }

 private:
  experimental::ClientRpcInfo* info_;
};

class HijackingInterceptorFactory
    : public experimental::ClientInterceptorFactoryInterface {
 public:
  virtual experimental::Interceptor* CreateClientInterceptor(
      experimental::ClientRpcInfo* info) override {
    return new HijackingInterceptor(info);
  }
};

class HijackingInterceptorMakesAnotherCall : public experimental::Interceptor {
 public:
  HijackingInterceptorMakesAnotherCall(experimental::ClientRpcInfo* info) {
    info_ = info;
    // Make sure it is the right method
    EXPECT_EQ(strcmp("/grpc.testing.EchoTestService/Echo", info->method()), 0);
  }

  virtual void Intercept(experimental::InterceptorBatchMethods* methods) {
    // gpr_log(GPR_ERROR, "ran this");
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_INITIAL_METADATA)) {
      auto* map = methods->GetSendInitialMetadata();
      // Check that we can see the test metadata
      ASSERT_EQ(map->size(), static_cast<unsigned>(1));
      auto iterator = map->begin();
      EXPECT_EQ("testkey", iterator->first);
      EXPECT_EQ("testvalue", iterator->second);
      // Make a copy of the map
      metadata_map_ = *map;
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_MESSAGE)) {
      EchoRequest req;
      auto* buffer = methods->GetSendMessage();
      auto copied_buffer = *buffer;
      SerializationTraits<EchoRequest>::Deserialize(&copied_buffer, &req);
      EXPECT_EQ(req.message(), "Hello");
      req_ = req;
      stub_ = grpc::testing::EchoTestService::NewStub(
          methods->GetInterceptedChannel());
      ctx_.AddMetadata(metadata_map_.begin()->first,
                       metadata_map_.begin()->second);
      stub_->experimental_async()->Echo(&ctx_, &req_, &resp_,
                                        [this, methods](Status s) {
                                          EXPECT_EQ(s.ok(), true);
                                          EXPECT_EQ(resp_.message(), "Hello");
                                          methods->Hijack();
                                        });
      // There isn't going to be any other interesting operation in this batch,
      // so it is fine to return
      return;
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_CLOSE)) {
      // Got nothing to do here for now
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_INITIAL_METADATA)) {
      auto* map = methods->GetRecvInitialMetadata();
      // Got nothing better to do here for now
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_MESSAGE)) {
      EchoResponse* resp =
          static_cast<EchoResponse*>(methods->GetRecvMessage());
      // Check that we got the hijacked message, and re-insert the expected
      // message
      EXPECT_EQ(resp->message(), "Hello");
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_STATUS)) {
      auto* map = methods->GetRecvTrailingMetadata();
      bool found = false;
      // Check that we received the metadata as an echo
      for (const auto& pair : *map) {
        found = pair.first.starts_with("testkey") &&
                pair.second.starts_with("testvalue");
        if (found) break;
      }
      EXPECT_EQ(found, true);
      auto* status = methods->GetRecvStatus();
      EXPECT_EQ(status->ok(), true);
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_INITIAL_METADATA)) {
      auto* map = methods->GetRecvInitialMetadata();
      // Got nothing better to do here at the moment
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_MESSAGE)) {
      // Insert a different message than expected
      EchoResponse* resp =
          static_cast<EchoResponse*>(methods->GetRecvMessage());
      resp->set_message(resp_.message());
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_RECV_STATUS)) {
      auto* map = methods->GetRecvTrailingMetadata();
      // insert the metadata that we want
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
      *map = ctx_.GetServerTrailingMetadata();
      auto* status = methods->GetRecvStatus();
      *status = Status(StatusCode::OK, "");
    }

    methods->Proceed();
  }

 private:
  experimental::ClientRpcInfo* info_;
  std::multimap<grpc::string, grpc::string> metadata_map_;
  ClientContext ctx_;
  EchoRequest req_;
  EchoResponse resp_;
  std::unique_ptr<grpc::testing::EchoTestService::Stub> stub_;
};

class HijackingInterceptorMakesAnotherCallFactory
    : public experimental::ClientInterceptorFactoryInterface {
 public:
  virtual experimental::Interceptor* CreateClientInterceptor(
      experimental::ClientRpcInfo* info) override {
    return new HijackingInterceptorMakesAnotherCall(info);
  }
};

class LoggingInterceptor : public experimental::Interceptor {
 public:
  LoggingInterceptor(experimental::ClientRpcInfo* info) { info_ = info; }

  virtual void Intercept(experimental::InterceptorBatchMethods* methods) {
    // gpr_log(GPR_ERROR, "ran this");
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_INITIAL_METADATA)) {
      auto* map = methods->GetSendInitialMetadata();
      // Check that we can see the test metadata
      ASSERT_EQ(map->size(), static_cast<unsigned>(1));
      auto iterator = map->begin();
      EXPECT_EQ("testkey", iterator->first);
      EXPECT_EQ("testvalue", iterator->second);
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_MESSAGE)) {
      EchoRequest req;
      auto* buffer = methods->GetSendMessage();
      auto copied_buffer = *buffer;
      SerializationTraits<EchoRequest>::Deserialize(&copied_buffer, &req);
      EXPECT_TRUE(req.message().find("Hello") == 0);
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::PRE_SEND_CLOSE)) {
      // Got nothing to do here for now
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_INITIAL_METADATA)) {
      auto* map = methods->GetRecvInitialMetadata();
      // Got nothing better to do here for now
      EXPECT_EQ(map->size(), static_cast<unsigned>(0));
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_MESSAGE)) {
      EchoResponse* resp =
          static_cast<EchoResponse*>(methods->GetRecvMessage());
      EXPECT_TRUE(resp->message().find("Hello") == 0);
    }
    if (methods->QueryInterceptionHookPoint(
            experimental::InterceptionHookPoints::POST_RECV_STATUS)) {
      auto* map = methods->GetRecvTrailingMetadata();
      bool found = false;
      // Check that we received the metadata as an echo
      for (const auto& pair : *map) {
        found = pair.first.starts_with("testkey") &&
                pair.second.starts_with("testvalue");
        if (found) break;
      }
      EXPECT_EQ(found, true);
      auto* status = methods->GetRecvStatus();
      EXPECT_EQ(status->ok(), true);
    }
    methods->Proceed();
  }

 private:
  experimental::ClientRpcInfo* info_;
};

class LoggingInterceptorFactory
    : public experimental::ClientInterceptorFactoryInterface {
 public:
  virtual experimental::Interceptor* CreateClientInterceptor(
      experimental::ClientRpcInfo* info) override {
    return new LoggingInterceptor(info);
  }
};

void MakeCall(const std::shared_ptr<Channel>& channel) {
  auto stub = grpc::testing::EchoTestService::NewStub(channel);
  ClientContext ctx;
  EchoRequest req;
  req.mutable_param()->set_echo_metadata(true);
  ctx.AddMetadata("testkey", "testvalue");
  req.set_message("Hello");
  EchoResponse resp;
  Status s = stub->Echo(&ctx, req, &resp);
  EXPECT_EQ(s.ok(), true);
  EXPECT_EQ(resp.message(), "Hello");
}

void MakeCallbackCall(const std::shared_ptr<Channel>& channel) {
  auto stub = grpc::testing::EchoTestService::NewStub(channel);
  ClientContext ctx;
  EchoRequest req;
  std::mutex mu;
  std::condition_variable cv;
  bool done = false;
  req.mutable_param()->set_echo_metadata(true);
  ctx.AddMetadata("testkey", "testvalue");
  req.set_message("Hello");
  EchoResponse resp;
  stub->experimental_async()->Echo(&ctx, &req, &resp,
                                   [&resp, &mu, &done, &cv](Status s) {
                                     // gpr_log(GPR_ERROR, "got the callback");
                                     EXPECT_EQ(s.ok(), true);
                                     EXPECT_EQ(resp.message(), "Hello");
                                     std::lock_guard<std::mutex> l(mu);
                                     done = true;
                                     cv.notify_one();
                                   });
  std::unique_lock<std::mutex> l(mu);
  while (!done) {
    cv.wait(l);
  }
}

void MakeStreamingCall(const std::shared_ptr<Channel>& channel) {
  auto stub = grpc::testing::EchoTestService::NewStub(channel);
  ClientContext ctx;
  EchoRequest req;
  EchoResponse resp;
  ctx.AddMetadata("testkey", "testvalue");
  auto stream = stub->BidiStream(&ctx);
  for (auto i = 0; i < 10; i++) {
    req.set_message("Hello" + std::to_string(i));
    stream->Write(req);
    stream->Read(&resp);
    EXPECT_EQ(req.message(), resp.message());
  }
  ASSERT_TRUE(stream->WritesDone());
  Status s = stream->Finish();
  EXPECT_EQ(s.ok(), true);
}

TEST_F(ClientInterceptorsEnd2endTest, ClientInterceptorLoggingTest) {
  ChannelArguments args;
  DummyInterceptor::Reset();
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  creators->push_back(std::unique_ptr<LoggingInterceptorFactory>(
      new LoggingInterceptorFactory()));
  // Add 20 dummy interceptors
  for (auto i = 0; i < 20; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  auto channel = experimental::CreateCustomChannelWithInterceptors(
      server_address_, InsecureChannelCredentials(), args, std::move(creators));
  MakeCall(channel);
  // Make sure all 20 dummy interceptors were run
  EXPECT_EQ(DummyInterceptor::GetNumTimesRun(), 20);
}

TEST_F(ClientInterceptorsEnd2endTest, ClientInterceptorHijackingTest) {
  ChannelArguments args;
  DummyInterceptor::Reset();
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  // Add 20 dummy interceptors before hijacking interceptor
  for (auto i = 0; i < 20; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  creators->push_back(std::unique_ptr<HijackingInterceptorFactory>(
      new HijackingInterceptorFactory()));
  // Add 20 dummy interceptors after hijacking interceptor
  for (auto i = 0; i < 20; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  auto channel = experimental::CreateCustomChannelWithInterceptors(
      server_address_, InsecureChannelCredentials(), args, std::move(creators));

  MakeCall(channel);
  // Make sure only 20 dummy interceptors were run
  EXPECT_EQ(DummyInterceptor::GetNumTimesRun(), 20);
}

TEST_F(ClientInterceptorsEnd2endTest, ClientInterceptorLogThenHijackTest) {
  ChannelArguments args;
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  creators->push_back(std::unique_ptr<LoggingInterceptorFactory>(
      new LoggingInterceptorFactory()));
  creators->push_back(std::unique_ptr<HijackingInterceptorFactory>(
      new HijackingInterceptorFactory()));
  auto channel = experimental::CreateCustomChannelWithInterceptors(
      server_address_, InsecureChannelCredentials(), args, std::move(creators));

  MakeCall(channel);
}

TEST_F(ClientInterceptorsEnd2endTest,
       ClientInterceptorHijackingMakesAnotherCallTest) {
  ChannelArguments args;
  DummyInterceptor::Reset();
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  // Add 5 dummy interceptors before hijacking interceptor
  for (auto i = 0; i < 5; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  creators->push_back(
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>(
          new HijackingInterceptorMakesAnotherCallFactory()));
  // Add 7 dummy interceptors after hijacking interceptor
  for (auto i = 0; i < 7; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  // auto channel = experimental::CreateCustomChannelWithInterceptors(
  //    server_address_, InsecureChannelCredentials(), args,
  //    std::move(creators));
  auto channel = server_->experimental().InProcessChannelWithInterceptors(
      args, std::move(creators));

  MakeCall(channel);
  // Make sure all interceptors were run once, since the hijacking interceptor
  // makes an RPC on the intercepted channel
  EXPECT_EQ(DummyInterceptor::GetNumTimesRun(), 12);
}

TEST_F(ClientInterceptorsEnd2endTest,
       ClientInterceptorLoggingTestWithCallback) {
  ChannelArguments args;
  DummyInterceptor::Reset();
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  creators->push_back(std::unique_ptr<LoggingInterceptorFactory>(
      new LoggingInterceptorFactory()));
  // Add 20 dummy interceptors
  for (auto i = 0; i < 20; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  auto channel = server_->experimental().InProcessChannelWithInterceptors(
      args, std::move(creators));
  MakeCallbackCall(channel);
  // Make sure all 20 dummy interceptors were run
  EXPECT_EQ(DummyInterceptor::GetNumTimesRun(), 20);
}

TEST_F(ClientInterceptorsStreamingEnd2EndTest, ClientInterceptorLoggingTest) {
  ChannelArguments args;
  DummyInterceptor::Reset();
  auto creators = std::unique_ptr<std::vector<
      std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>>(
      new std::vector<
          std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>());
  creators->push_back(std::unique_ptr<LoggingInterceptorFactory>(
      new LoggingInterceptorFactory()));
  // Add 20 dummy interceptors
  for (auto i = 0; i < 20; i++) {
    creators->push_back(std::unique_ptr<DummyInterceptorFactory>(
        new DummyInterceptorFactory()));
  }
  auto channel = experimental::CreateCustomChannelWithInterceptors(
      server_address_, InsecureChannelCredentials(), args, std::move(creators));
  MakeStreamingCall(channel);
  // Make sure all 20 dummy interceptors were run
  EXPECT_EQ(DummyInterceptor::GetNumTimesRun(), 20);
}

}  // namespace
}  // namespace testing
}  // namespace grpc

int main(int argc, char** argv) {
  grpc_test_init(argc, argv);
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}