text: // Copyright 2020 Google LLC
  //
  // 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 "tink/cc/output_stream_adapter.h"
  
  #include <algorithm>
  #include <sstream>
  #include <string>
  #include <utility>
  
  #include "gmock/gmock.h"
  #include "gtest/gtest.h"
  #include "absl/memory/memory.h"
  #include "absl/status/status.h"
  #include "tink/output_stream.h"
  #include "tink/subtle/random.h"
  #include "tink/util/ostream_output_stream.h"
  
  namespace crypto {
  namespace tink {
  namespace {
  
  std::unique_ptr<OutputStreamAdapter> GetOutputStreamAdapter(
      int buffer_size, std::stringbuf** buffer_ref) {
    auto string_stream = absl::make_unique<std::stringstream>();
    // Reference to the stringstream buffer used for later validation.
    *buffer_ref = string_stream->rdbuf();
    auto output_stream = absl::make_unique<util::OstreamOutputStream>(
        std::move(string_stream), buffer_size);
    return absl::make_unique<OutputStreamAdapter>(std::move(output_stream));
  }
  
  TEST(OutputStreamAdapterTest, Basic) {
    std::stringbuf* buffer_ref;
    auto adapter = GetOutputStreamAdapter(-1, &buffer_ref);
    auto write_result = adapter->Write("something");
    ASSERT_TRUE(write_result.status().ok());
    EXPECT_EQ(write_result.value(), 9);
    EXPECT_TRUE(adapter->Close().ok());
    EXPECT_EQ(buffer_ref->str(), "something");
  }
  
  TEST(OutputStreamAdapterTest, MultipleWrite) {
    std::stringbuf* buffer_ref;
    auto adapter = GetOutputStreamAdapter(-1, &buffer_ref);
    auto write_result = adapter->Write("something");
    ASSERT_TRUE(write_result.status().ok());
    EXPECT_EQ(write_result.value(), 9);
    write_result = adapter->Write("123");
    ASSERT_TRUE(write_result.status().ok());
    EXPECT_EQ(write_result.value(), 3);
    write_result = adapter->Write("456");
    ASSERT_TRUE(write_result.status().ok());
    EXPECT_EQ(write_result.value(), 3);
    EXPECT_TRUE(adapter->Close().ok());
    EXPECT_EQ(buffer_ref->str(), "something123456");
  }
  
  TEST(OutputStreamAdapterTest, WriteAfterClose) {
    std::stringbuf* buffer_ref;
    auto adapter = GetOutputStreamAdapter(-1, &buffer_ref);
    ASSERT_TRUE(adapter->Close().ok());
    auto status = adapter->Write("something").status();
    EXPECT_EQ(status.code(), absl::StatusCode::kFailedPrecondition);
    EXPECT_THAT(std::string(status.message()),
                testing::HasSubstr("Stream closed"));
  }
  
  // In this test size of the OstreamOutputStream buffer is smaller than the
  // size of data to be written, so multiple calls to Next() will be needed.
  TEST(OutputStreamAdapterTest, MultipleNext) {
    std::stringbuf* buffer_ref;
    auto adapter = GetOutputStreamAdapter(10, &buffer_ref);
    std::string data = subtle::Random::GetRandomBytes(35);
    auto write_result = adapter->Write(data);
    ASSERT_TRUE(write_result.status().ok());
    EXPECT_EQ(write_result.value(), 35);
    EXPECT_TRUE(adapter->Close().ok());
    EXPECT_EQ(buffer_ref->str(), data);
  }
  
  }  // namespace
  }  // namespace tink
  }  // namespace crypto
  