#include "http2/adapter/nghttp2_adapter.h"

#include "http2/adapter/http2_protocol.h"
#include "http2/adapter/mock_http2_visitor.h"
#include "http2/adapter/nghttp2_test_utils.h"
#include "http2/adapter/oghttp2_util.h"
#include "http2/adapter/test_frame_sequence.h"
#include "http2/adapter/test_utils.h"
#include "common/platform/api/quiche_test.h"

namespace http2 {
namespace adapter {
namespace test {
namespace {

using testing::_;

enum FrameType {
  DATA,
  HEADERS,
  PRIORITY,
  RST_STREAM,
  SETTINGS,
  PUSH_PROMISE,
  PING,
  GOAWAY,
  WINDOW_UPDATE,
  CONTINUATION,
};

// This send callback assumes |source|'s pointer is a TestDataSource, and
// |user_data| is a Http2VisitorInterface.
int TestSendCallback(nghttp2_session*, nghttp2_frame* /*frame*/,
                     const uint8_t* framehd, size_t length,
                     nghttp2_data_source* source, void* user_data) {
  auto* visitor = static_cast<Http2VisitorInterface*>(user_data);
  // Send the frame header via the visitor.
  ssize_t result = visitor->OnReadyToSend(ToStringView(framehd, 9));
  if (result == 0) {
    return NGHTTP2_ERR_WOULDBLOCK;
  }
  auto* test_source = static_cast<TestDataSource*>(source->ptr);
  absl::string_view payload = test_source->ReadNext(length);
  // Send the frame payload via the visitor.
  visitor->OnReadyToSend(payload);
  return 0;
}

TEST(NgHttp2AdapterTest, ClientConstruction) {
  testing::StrictMock<MockHttp2Visitor> visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);
  ASSERT_NE(nullptr, adapter);
  EXPECT_TRUE(adapter->want_read());
  EXPECT_FALSE(adapter->want_write());
  EXPECT_FALSE(adapter->IsServerSession());
}

TEST(NgHttp2AdapterTest, ClientHandlesFrames) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);
  int result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(),
              testing::StrEq(spdy::kHttp2ConnectionHeaderPrefix));
  visitor.Clear();

  EXPECT_EQ(0, adapter->GetHighestReceivedStreamId());

  const std::string initial_frames = TestFrameSequence()
                                         .ServerPreface()
                                         .Ping(42)
                                         .WindowUpdate(0, 1000)
                                         .Serialize();
  testing::InSequence s;

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(0, 8, PING, 0));
  EXPECT_CALL(visitor, OnPing(42, false));
  EXPECT_CALL(visitor, OnFrameHeader(0, 4, WINDOW_UPDATE, 0));
  EXPECT_CALL(visitor, OnWindowUpdate(0, 1000));

  const int64_t initial_result = adapter->ProcessBytes(initial_frames);
  EXPECT_EQ(initial_frames.size(), initial_result);

  EXPECT_EQ(adapter->GetSendWindowSize(), kInitialFlowControlWindowSize + 1000);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(PING, 0, 8, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(PING, 0, 8, 0x1, 0));

  result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::PING}));
  visitor.Clear();

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const std::vector<const Header> headers2 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/two"}});

  const std::vector<const Header> headers3 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/three"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const char* kSentinel3 = "arbitrary pointer 3";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  const int32_t stream_id2 = adapter->SubmitRequest(headers2, nullptr, nullptr);
  ASSERT_GT(stream_id2, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id2;

  const int32_t stream_id3 =
      adapter->SubmitRequest(headers3, nullptr, const_cast<char*>(kSentinel3));
  ASSERT_GT(stream_id3, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id3;

  const char* kSentinel2 = "arbitrary pointer 2";
  adapter->SetStreamUserData(stream_id2, const_cast<char*>(kSentinel2));
  adapter->SetStreamUserData(stream_id3, nullptr);

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id2, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id2, _, 0x5, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id3, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id3, _, 0x5, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  // All streams are active and have not yet received any data, so the receive
  // window should be at the initial value.
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id1));
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id2));
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id3));

  // Upper bound on the flow control receive window should be the initial value.
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowLimit(stream_id1));

  // Connection has not yet received any data.
  EXPECT_EQ(kInitialFlowControlWindowSize, adapter->GetReceiveWindowSize());

  EXPECT_EQ(0, adapter->GetHighestReceivedStreamId());

  EXPECT_EQ(kSentinel1, adapter->GetStreamUserData(stream_id1));
  EXPECT_EQ(kSentinel2, adapter->GetStreamUserData(stream_id2));
  EXPECT_EQ(nullptr, adapter->GetStreamUserData(stream_id3));

  EXPECT_EQ(0, adapter->GetHpackDecoderDynamicTableSize());

  const std::string stream_frames =
      TestFrameSequence()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .RstStream(3, Http2ErrorCode::INTERNAL_ERROR)
          .GoAway(5, Http2ErrorCode::ENHANCE_YOUR_CALM, "calm down!!")
          .Serialize();

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 26, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 26));
  EXPECT_CALL(visitor, OnDataForStream(1, "This is the response body."));
  EXPECT_CALL(visitor, OnFrameHeader(3, 4, RST_STREAM, 0));
  EXPECT_CALL(visitor, OnRstStream(3, Http2ErrorCode::INTERNAL_ERROR));
  EXPECT_CALL(visitor, OnCloseStream(3, Http2ErrorCode::INTERNAL_ERROR));
  EXPECT_CALL(visitor, OnFrameHeader(0, 19, GOAWAY, 0));
  EXPECT_CALL(visitor,
              OnGoAway(5, Http2ErrorCode::ENHANCE_YOUR_CALM, "calm down!!"));
  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);

  // First stream has received some data.
  EXPECT_GT(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id1));
  // Second stream was closed.
  EXPECT_EQ(-1, adapter->GetStreamReceiveWindowSize(stream_id2));
  // Third stream has not received any data.
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id3));

  // Connection window should be the same as the first stream.
  EXPECT_EQ(adapter->GetReceiveWindowSize(),
            adapter->GetStreamReceiveWindowSize(stream_id1));

  // Upper bound on the flow control receive window should still be the initial
  // value.
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowLimit(stream_id1));

  EXPECT_GT(adapter->GetHpackDecoderDynamicTableSize(), 0);

  // Should be 3, but this method only works for server adapters.
  EXPECT_EQ(0, adapter->GetHighestReceivedStreamId());

  // Even though the client recieved a GOAWAY, streams 1 and 5 are still active.
  EXPECT_TRUE(adapter->want_read());

  EXPECT_CALL(visitor, OnFrameHeader(1, 0, DATA, 1));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 0));
  EXPECT_CALL(visitor, OnEndStream(1));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::NO_ERROR));
  EXPECT_CALL(visitor, OnFrameHeader(5, 4, RST_STREAM, 0));
  EXPECT_CALL(visitor, OnRstStream(5, Http2ErrorCode::REFUSED_STREAM));
  EXPECT_CALL(visitor, OnCloseStream(5, Http2ErrorCode::REFUSED_STREAM));
  adapter->ProcessBytes(TestFrameSequence()
                            .Data(1, "", true)
                            .RstStream(5, Http2ErrorCode::REFUSED_STREAM)
                            .Serialize());

  // Should be 5, but this method only works for server adapters.
  EXPECT_EQ(0, adapter->GetHighestReceivedStreamId());

  // After receiving END_STREAM for 1 and RST_STREAM for 5, the session no
  // longer expects reads.
  EXPECT_FALSE(adapter->want_read());

  // Client will not have anything else to write.
  EXPECT_FALSE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), testing::IsEmpty());
}

TEST(NgHttp2AdapterTest, ClientHandlesTrailers) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .Headers(1, {{"final-status", "A-OK"}},
                   /*fin=*/true)
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 26, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 26));
  EXPECT_CALL(visitor, OnDataForStream(1, "This is the response body."));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "final-status", "A-OK"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnEndStream(1));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::NO_ERROR));

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, _, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, _, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientHandlesMetadata) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Metadata(0, "Example connection metadata")
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Metadata(1, "Example stream metadata")
          .Data(1, "This is the response body.", true)
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(0, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataEndForStream(0));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataEndForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 26, DATA, 1));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 26));
  EXPECT_CALL(visitor, OnDataForStream(1, "This is the response body."));
  EXPECT_CALL(visitor, OnEndStream(1));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::NO_ERROR));

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, _, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, _, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientHandlesMetadataWithError) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Metadata(0, "Example connection metadata")
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Metadata(1, "Example stream metadata")
          .Data(1, "This is the response body.", true)
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(0, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataEndForStream(0));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataForStream(1, _))
      .WillOnce(testing::Return(false));
  // Remaining frames are not processed due to the error.
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  // The false return from OnMetadataForStream() results in a connection error.
  EXPECT_EQ(stream_result, NGHTTP2_ERR_CALLBACK_FAILURE);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, _, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, _, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  EXPECT_TRUE(adapter->want_read());  // Even after an error. Why?
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientHandlesInvalidTrailers) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .Headers(1, {{":bad-status", "9000"}},
                   /*fin=*/true)
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 26, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 26));
  EXPECT_CALL(visitor, OnDataForStream(1, "This is the response body."));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(
      visitor,
      OnErrorDebug("Invalid HTTP header field was received: frame type: 1, "
                   "stream: 1, name: [:bad-status], value: [9000]"));
  EXPECT_CALL(visitor, OnInvalidFrame(1, -531));

  // Bad status trailer will cause a PROTOCOL_ERROR. The header is never
  // delivered in an OnHeaderForStream callback.

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(RST_STREAM, stream_id1, 4, 0x0));
  EXPECT_CALL(visitor, OnFrameSent(RST_STREAM, stream_id1, 4, 0x0, 1));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::PROTOCOL_ERROR));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::RST_STREAM}));
}

TEST(NgHttp2AdapterTest, ClientRstStreamWhileHandlingHeaders) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"))
      .WillOnce(testing::DoAll(
          testing::InvokeWithoutArgs([&adapter]() {
            adapter->SubmitRst(1, Http2ErrorCode::REFUSED_STREAM);
          }),
          testing::Return(Http2VisitorInterface::HEADER_RST_STREAM)));

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(RST_STREAM, stream_id1, 4, 0x0));
  EXPECT_CALL(visitor,
              OnFrameSent(RST_STREAM, stream_id1, 4, 0x0,
                          static_cast<int>(Http2ErrorCode::REFUSED_STREAM)));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::REFUSED_STREAM));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::RST_STREAM}));
}

TEST(NgHttp2AdapterTest, ClientConnectionErrorWhileHandlingHeaders) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"))
      .WillOnce(
          testing::Return(Http2VisitorInterface::HEADER_CONNECTION_ERROR));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(-902 /* NGHTTP2_ERR_CALLBACK_FAILURE */, stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientRejectsHeaders) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(1, "This is the response body.")
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1))
      .WillOnce(testing::Return(false));
  // Rejecting headers leads to a connection error.
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(NGHTTP2_ERR_CALLBACK_FAILURE, stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientFailsOnGoAway) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  testing::InSequence s;

  const std::vector<const Header> headers1 =
      ToHeaders({{":method", "GET"},
                 {":scheme", "http"},
                 {":authority", "example.com"},
                 {":path", "/this/is/request/one"}});

  const char* kSentinel1 = "arbitrary pointer 1";
  const int32_t stream_id1 =
      adapter->SubmitRequest(headers1, nullptr, const_cast<char*>(kSentinel1));
  ASSERT_GT(stream_id1, 0);
  QUICHE_LOG(INFO) << "Created stream: " << stream_id1;

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id1, _, 0x5, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view data = visitor.data();
  EXPECT_THAT(data, testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  data.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(data, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();

  const std::string stream_frames =
      TestFrameSequence()
          .ServerPreface()
          .Headers(1,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .GoAway(1, Http2ErrorCode::INTERNAL_ERROR, "indigestion")
          .Data(1, "This is the response body.")
          .Serialize();

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":status", "200"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "server", "my-fake-server"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(1, "date", "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(0, _, GOAWAY, 0));
  EXPECT_CALL(visitor,
              OnGoAway(1, Http2ErrorCode::INTERNAL_ERROR, "indigestion"))
      .WillOnce(testing::Return(false));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(NGHTTP2_ERR_CALLBACK_FAILURE, stream_result);

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  EXPECT_TRUE(adapter->want_write());
  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ClientSubmitRequest) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);
  int result = adapter->Send();
  EXPECT_EQ(0, result);
  // Client preface does not appear to include the mandatory SETTINGS frame.
  EXPECT_THAT(visitor.data(),
              testing::StrEq(spdy::kHttp2ConnectionHeaderPrefix));
  visitor.Clear();

  const std::string initial_frames =
      TestFrameSequence().ServerPreface().Serialize();
  testing::InSequence s;

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  const int64_t initial_result = adapter->ProcessBytes(initial_frames);
  EXPECT_EQ(initial_frames.size(), initial_result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
  visitor.Clear();

  EXPECT_EQ(0, adapter->GetHpackEncoderDynamicTableSize());
  EXPECT_FALSE(adapter->want_write());
  const char* kSentinel = "";
  const absl::string_view kBody = "This is an example request body.";
  auto body1 = absl::make_unique<TestDataFrameSource>(visitor, true);
  body1->AppendPayload(kBody);
  body1->EndData();
  int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(body1), const_cast<char*>(kSentinel));
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, _, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);

  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(stream_id));
  EXPECT_EQ(kInitialFlowControlWindowSize, adapter->GetReceiveWindowSize());
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowLimit(stream_id));

  EXPECT_GT(adapter->GetHpackEncoderDynamicTableSize(), 0);

  // Some data was sent, so the remaining send window size should be less than
  // the default.
  EXPECT_LT(adapter->GetStreamSendWindowSize(stream_id),
            kInitialFlowControlWindowSize);
  EXPECT_GT(adapter->GetStreamSendWindowSize(stream_id), 0);
  // Send window for a nonexistent stream is not available.
  EXPECT_EQ(-1, adapter->GetStreamSendWindowSize(stream_id + 2));

  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             nullptr, nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());
  const char* kSentinel2 = "arbitrary pointer 2";
  EXPECT_EQ(nullptr, adapter->GetStreamUserData(stream_id));
  adapter->SetStreamUserData(stream_id, const_cast<char*>(kSentinel2));

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x5, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS}));

  EXPECT_EQ(kSentinel2, adapter->GetStreamUserData(stream_id));

  // No data was sent (just HEADERS), so the remaining send window size should
  // still be the default.
  EXPECT_EQ(adapter->GetStreamSendWindowSize(stream_id),
            kInitialFlowControlWindowSize);
}

// This is really a test of the MakeZeroCopyDataFrameSource adapter, but I
// wasn't sure where else to put it.
TEST(NgHttp2AdapterTest, ClientSubmitRequestWithDataProvider) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);
  int result = adapter->Send();
  EXPECT_EQ(0, result);
  // Client preface does not appear to include the mandatory SETTINGS frame.
  EXPECT_THAT(visitor.data(),
              testing::StrEq(spdy::kHttp2ConnectionHeaderPrefix));
  visitor.Clear();

  const std::string initial_frames =
      TestFrameSequence().ServerPreface().Serialize();
  testing::InSequence s;

  // Server preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  const int64_t initial_result = adapter->ProcessBytes(initial_frames);
  EXPECT_EQ(initial_frames.size(), initial_result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
  visitor.Clear();

  EXPECT_FALSE(adapter->want_write());
  const absl::string_view kBody = "This is an example request body.";
  // This test will use TestDataSource as the source of the body payload data.
  TestDataSource body1{kBody};
  // The TestDataSource is wrapped in the nghttp2_data_provider data type.
  nghttp2_data_provider provider = body1.MakeDataProvider();
  nghttp2_send_data_callback send_callback = &TestSendCallback;

  // This call transforms it back into a DataFrameSource, which is compatible
  // with the Http2Adapter API.
  std::unique_ptr<DataFrameSource> frame_source =
      MakeZeroCopyDataFrameSource(provider, &visitor, std::move(send_callback));
  int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(frame_source), nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, _, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  EXPECT_FALSE(adapter->want_write());
}

// This test verifies how nghttp2 behaves when a data source becomes
// read-blocked.
TEST(NgHttp2AdapterTest, ClientSubmitRequestWithDataProviderAndReadBlock) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  const absl::string_view kBody = "This is an example request body.";
  // This test will use TestDataSource as the source of the body payload data.
  TestDataSource body1{kBody};
  body1.set_is_data_available(false);
  // The TestDataSource is wrapped in the nghttp2_data_provider data type.
  nghttp2_data_provider provider = body1.MakeDataProvider();
  nghttp2_send_data_callback send_callback = &TestSendCallback;

  // This call transforms it back into a DataFrameSource, which is compatible
  // with the Http2Adapter API.
  std::unique_ptr<DataFrameSource> frame_source =
      MakeZeroCopyDataFrameSource(provider, &visitor, std::move(send_callback));
  int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(frame_source), nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  // Client preface does not appear to include the mandatory SETTINGS frame.
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(serialized, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  // Resume the deferred stream.
  body1.set_is_data_available(true);
  EXPECT_TRUE(adapter->ResumeStream(stream_id));
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, _, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::DATA}));
  EXPECT_FALSE(adapter->want_write());

  // Stream data is done, so this stream cannot be resumed.
  EXPECT_FALSE(adapter->ResumeStream(stream_id));
  EXPECT_FALSE(adapter->want_write());
}

// This test verifies how nghttp2 behaves when a data source is read block, then
// ends with an empty DATA frame.
TEST(NgHttp2AdapterTest, ClientSubmitRequestEmptyDataWithFin) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  const absl::string_view kEmptyBody = "";
  // This test will use TestDataSource as the source of the body payload data.
  TestDataSource body1{kEmptyBody};
  body1.set_is_data_available(false);
  // The TestDataSource is wrapped in the nghttp2_data_provider data type.
  nghttp2_data_provider provider = body1.MakeDataProvider();
  nghttp2_send_data_callback send_callback = &TestSendCallback;

  // This call transforms it back into a DataFrameSource, which is compatible
  // with the Http2Adapter API.
  std::unique_ptr<DataFrameSource> frame_source =
      MakeZeroCopyDataFrameSource(provider, &visitor, std::move(send_callback));
  int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(frame_source), nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  // Client preface does not appear to include the mandatory SETTINGS frame.
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(serialized, EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  // Resume the deferred stream.
  body1.set_is_data_available(true);
  EXPECT_TRUE(adapter->ResumeStream(stream_id));
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, 0, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::DATA}));
  EXPECT_FALSE(adapter->want_write());

  // Stream data is done, so this stream cannot be resumed.
  EXPECT_FALSE(adapter->ResumeStream(stream_id));
  EXPECT_FALSE(adapter->want_write());
}

// This test verifies how nghttp2 behaves when a connection becomes
// write-blocked.
TEST(NgHttp2AdapterTest, ClientSubmitRequestWithDataProviderAndWriteBlock) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  const absl::string_view kBody = "This is an example request body.";
  // This test will use TestDataSource as the source of the body payload data.
  TestDataSource body1{kBody};
  // The TestDataSource is wrapped in the nghttp2_data_provider data type.
  nghttp2_data_provider provider = body1.MakeDataProvider();
  nghttp2_send_data_callback send_callback = &TestSendCallback;

  // This call transforms it back into a DataFrameSource, which is compatible
  // with the Http2Adapter API.
  std::unique_ptr<DataFrameSource> frame_source =
      MakeZeroCopyDataFrameSource(provider, &visitor, std::move(send_callback));
  int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(frame_source), nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  visitor.set_is_write_blocked(true);
  int result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), testing::IsEmpty());
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, _, 0x1, 0));

  visitor.set_is_write_blocked(false);
  result = adapter->Send();
  EXPECT_EQ(0, result);

  // Client preface does not appear to include the mandatory SETTINGS frame.
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(serialized, EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                        spdy::SpdyFrameType::DATA}));
  EXPECT_FALSE(adapter->want_write());
}

TEST(NgHttp2AdapterTest, SubmitMetadata) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  auto source = absl::make_unique<TestMetadataSource>(ToHeaderBlock(ToHeaders(
      {{"query-cost", "is too darn high"}, {"secret-sauce", "hollandaise"}})));
  adapter->SubmitMetadata(1, 16384u, std::move(source));
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 1, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 1, _, 0x4, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(
      serialized,
      EqualsFrames({static_cast<spdy::SpdyFrameType>(kMetadataFrameType)}));
  EXPECT_FALSE(adapter->want_write());
}

TEST(NgHttp2AdapterTest, SubmitMetadataMultipleFrames) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  const auto kLargeValue = std::string(63 * 1024, 'a');
  auto source = absl::make_unique<TestMetadataSource>(
      ToHeaderBlock(ToHeaders({{"large-value", kLargeValue}})));
  adapter->SubmitMetadata(1, 16384u, std::move(source));
  EXPECT_TRUE(adapter->want_write());

  testing::InSequence seq;
  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 1, _, 0x0));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 1, _, 0x0, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 1, _, 0x0));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 1, _, 0x0, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 1, _, 0x0));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 1, _, 0x0, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 1, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 1, _, 0x4, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(
      serialized,
      EqualsFrames({static_cast<spdy::SpdyFrameType>(kMetadataFrameType),
                    static_cast<spdy::SpdyFrameType>(kMetadataFrameType),
                    static_cast<spdy::SpdyFrameType>(kMetadataFrameType),
                    static_cast<spdy::SpdyFrameType>(kMetadataFrameType)}));
  EXPECT_FALSE(adapter->want_write());
}

TEST(NgHttp2AdapterTest, SubmitConnectionMetadata) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);

  auto source = absl::make_unique<TestMetadataSource>(ToHeaderBlock(ToHeaders(
      {{"query-cost", "is too darn high"}, {"secret-sauce", "hollandaise"}})));
  adapter->SubmitMetadata(0, 16384u, std::move(source));
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(kMetadataFrameType, 0, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(kMetadataFrameType, 0, _, 0x4, 0));

  int result = adapter->Send();
  EXPECT_EQ(0, result);
  absl::string_view serialized = visitor.data();
  EXPECT_THAT(serialized,
              testing::StartsWith(spdy::kHttp2ConnectionHeaderPrefix));
  serialized.remove_prefix(strlen(spdy::kHttp2ConnectionHeaderPrefix));
  EXPECT_THAT(
      serialized,
      EqualsFrames({static_cast<spdy::SpdyFrameType>(kMetadataFrameType)}));
  EXPECT_FALSE(adapter->want_write());
}

TEST(NgHttp2AdapterTest, ClientObeysMaxConcurrentStreams) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateClientAdapter(visitor);
  int result = adapter->Send();
  EXPECT_EQ(0, result);
  // Client preface does not appear to include the mandatory SETTINGS frame.
  EXPECT_THAT(visitor.data(),
              testing::StrEq(spdy::kHttp2ConnectionHeaderPrefix));
  visitor.Clear();

  const std::string initial_frames =
      TestFrameSequence()
          .ServerPreface({{.id = MAX_CONCURRENT_STREAMS, .value = 1}})
          .Serialize();
  testing::InSequence s;

  // Server preface (SETTINGS with MAX_CONCURRENT_STREAMS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 6, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSetting);
  EXPECT_CALL(visitor, OnSettingsEnd());

  const int64_t initial_result = adapter->ProcessBytes(initial_frames);
  EXPECT_EQ(initial_frames.size(), initial_result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
  visitor.Clear();

  EXPECT_FALSE(adapter->want_write());
  const absl::string_view kBody = "This is an example request body.";
  auto body1 = absl::make_unique<TestDataFrameSource>(visitor, true);
  body1->AppendPayload(kBody);
  body1->EndData();
  const int stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/one"}}),
                             std::move(body1), nullptr);
  EXPECT_GT(stream_id, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, stream_id, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, stream_id, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, stream_id, _, 0x1, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);

  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  const int next_stream_id =
      adapter->SubmitRequest(ToHeaders({{":method", "POST"},
                                        {":scheme", "http"},
                                        {":authority", "example.com"},
                                        {":path", "/this/is/request/two"}}),
                             nullptr, nullptr);

  // A new pending stream is created, but because of MAX_CONCURRENT_STREAMS, the
  // session should not want to write it at the moment.
  EXPECT_GT(next_stream_id, stream_id);
  EXPECT_FALSE(adapter->want_write());

  const std::string stream_frames =
      TestFrameSequence()
          .Headers(stream_id,
                   {{":status", "200"},
                    {"server", "my-fake-server"},
                    {"date", "Tue, 6 Apr 2021 12:54:01 GMT"}},
                   /*fin=*/false)
          .Data(stream_id, "This is the response body.", /*fin=*/true)
          .Serialize();

  EXPECT_CALL(visitor, OnFrameHeader(stream_id, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(stream_id));
  EXPECT_CALL(visitor, OnHeaderForStream(stream_id, ":status", "200"));
  EXPECT_CALL(visitor,
              OnHeaderForStream(stream_id, "server", "my-fake-server"));
  EXPECT_CALL(visitor, OnHeaderForStream(stream_id, "date",
                                         "Tue, 6 Apr 2021 12:54:01 GMT"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(stream_id));
  EXPECT_CALL(visitor, OnFrameHeader(stream_id, 26, DATA, 0x1));
  EXPECT_CALL(visitor, OnBeginDataForStream(stream_id, 26));
  EXPECT_CALL(visitor,
              OnDataForStream(stream_id, "This is the response body."));
  EXPECT_CALL(visitor, OnEndStream(stream_id));
  EXPECT_CALL(visitor, OnCloseStream(stream_id, Http2ErrorCode::NO_ERROR));

  // The first stream should close, which should make the session want to write
  // the next stream.
  const int64_t stream_result = adapter->ProcessBytes(stream_frames);
  EXPECT_EQ(stream_frames.size(), stream_result);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, next_stream_id, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, next_stream_id, _, 0x5, 0));

  result = adapter->Send();
  EXPECT_EQ(0, result);

  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS}));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());
}

TEST(NgHttp2AdapterTest, ServerConstruction) {
  testing::StrictMock<MockHttp2Visitor> visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  ASSERT_NE(nullptr, adapter);
  EXPECT_TRUE(adapter->want_read());
  EXPECT_FALSE(adapter->want_write());
  EXPECT_TRUE(adapter->IsServerSession());
}

TEST(NgHttp2AdapterTest, ServerHandlesFrames) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  EXPECT_EQ(0, adapter->GetHighestReceivedStreamId());
  EXPECT_EQ(0, adapter->GetHpackDecoderDynamicTableSize());

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Ping(42)
                                 .WindowUpdate(0, 1000)
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .WindowUpdate(1, 2000)
                                 .Data(1, "This is the request body.")
                                 .Headers(3,
                                          {{":method", "GET"},
                                           {":scheme", "http"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/two"}},
                                          /*fin=*/true)
                                 .RstStream(3, Http2ErrorCode::CANCEL)
                                 .Ping(47)
                                 .Serialize();
  testing::InSequence s;

  const char* kSentinel1 = "arbitrary pointer 1";

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(0, 8, PING, 0));
  EXPECT_CALL(visitor, OnPing(42, false));
  EXPECT_CALL(visitor, OnFrameHeader(0, 4, WINDOW_UPDATE, 0));
  EXPECT_CALL(visitor, OnWindowUpdate(0, 1000));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1))
      .WillOnce(testing::InvokeWithoutArgs([&adapter, kSentinel1]() {
        adapter->SetStreamUserData(1, const_cast<char*>(kSentinel1));
        return true;
      }));
  EXPECT_CALL(visitor, OnFrameHeader(1, 4, WINDOW_UPDATE, 0));
  EXPECT_CALL(visitor, OnWindowUpdate(1, 2000));
  EXPECT_CALL(visitor, OnFrameHeader(1, 25, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 25));
  EXPECT_CALL(visitor, OnDataForStream(1, "This is the request body."));
  EXPECT_CALL(visitor, OnFrameHeader(3, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(3));
  EXPECT_CALL(visitor, OnHeaderForStream(3, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(3, ":scheme", "http"));
  EXPECT_CALL(visitor, OnHeaderForStream(3, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(3, ":path", "/this/is/request/two"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(3));
  EXPECT_CALL(visitor, OnEndStream(3));
  EXPECT_CALL(visitor, OnFrameHeader(3, 4, RST_STREAM, 0));
  EXPECT_CALL(visitor, OnRstStream(3, Http2ErrorCode::CANCEL));
  EXPECT_CALL(visitor, OnCloseStream(3, Http2ErrorCode::CANCEL));
  EXPECT_CALL(visitor, OnFrameHeader(0, 8, PING, 0));
  EXPECT_CALL(visitor, OnPing(47, false));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  EXPECT_EQ(kSentinel1, adapter->GetStreamUserData(1));

  EXPECT_GT(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowSize(1));
  EXPECT_EQ(adapter->GetStreamReceiveWindowSize(1),
            adapter->GetReceiveWindowSize());
  // Upper bound should still be the original value.
  EXPECT_EQ(kInitialFlowControlWindowSize,
            adapter->GetStreamReceiveWindowLimit(1));

  EXPECT_GT(adapter->GetHpackDecoderDynamicTableSize(), 0);

  // Because stream 3 has already been closed, it's not possible to set user
  // data.
  const char* kSentinel3 = "another arbitrary pointer";
  adapter->SetStreamUserData(3, const_cast<char*>(kSentinel3));
  EXPECT_EQ(nullptr, adapter->GetStreamUserData(3));

  EXPECT_EQ(3, adapter->GetHighestReceivedStreamId());

  EXPECT_EQ(adapter->GetSendWindowSize(), kInitialFlowControlWindowSize + 1000);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(PING, 0, 8, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(PING, 0, 8, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(PING, 0, 8, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(PING, 0, 8, 0x1, 0));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack, two PING acks.
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::PING,
                                            spdy::SpdyFrameType::PING}));
}

TEST(NgHttp2AdapterTest, ServerErrorWhileHandlingHeaders) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"},
                                           {"accept", "some bogus value!"}},
                                          /*fin=*/false)
                                 .WindowUpdate(1, 2000)
                                 .Data(1, "This is the request body.")
                                 .WindowUpdate(0, 2000)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, "accept", "some bogus value!"))
      .WillOnce(testing::Return(Http2VisitorInterface::HEADER_RST_STREAM));
  EXPECT_CALL(visitor, OnFrameHeader(1, 4, WINDOW_UPDATE, 0));
  EXPECT_CALL(visitor, OnWindowUpdate(1, 2000));
  // DATA frame is not delivered to the visitor.
  EXPECT_CALL(visitor, OnFrameHeader(0, 4, WINDOW_UPDATE, 0));
  EXPECT_CALL(visitor, OnWindowUpdate(0, 2000));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(RST_STREAM, 1, 4, 0x0));
  EXPECT_CALL(visitor,
              OnFrameSent(RST_STREAM, 1, 4, 0x0,
                          static_cast<int>(Http2ErrorCode::INTERNAL_ERROR)));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::INTERNAL_ERROR));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::RST_STREAM}));
}

TEST(NgHttp2AdapterTest, ServerErrorAfterHandlingHeaders) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .WindowUpdate(1, 2000)
                                 .Data(1, "This is the request body.")
                                 .WindowUpdate(0, 2000)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1))
      .WillOnce(testing::Return(false));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(-902, result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

// Exercises the case when a visitor chooses to reject a frame based solely on
// the frame header, which is a fatal error for the connection.
TEST(NgHttp2AdapterTest, ServerRejectsFrameHeader) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Ping(64)
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .WindowUpdate(1, 2000)
                                 .Data(1, "This is the request body.")
                                 .WindowUpdate(0, 2000)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(0, 8, PING, 0))
      .WillOnce(testing::Return(false));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(-902, result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ServerRejectsBeginningOfData) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .Data(1, "This is the request body.")
                                 .Headers(3,
                                          {{":method", "GET"},
                                           {":scheme", "http"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/two"}},
                                          /*fin=*/true)
                                 .RstStream(3, Http2ErrorCode::CANCEL)
                                 .Ping(47)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 25, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 25))
      .WillOnce(testing::Return(false));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(NGHTTP2_ERR_CALLBACK_FAILURE, result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack.
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ServerRejectsStreamData) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .Data(1, "This is the request body.")
                                 .Headers(3,
                                          {{":method", "GET"},
                                           {":scheme", "http"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/two"}},
                                          /*fin=*/true)
                                 .RstStream(3, Http2ErrorCode::CANCEL)
                                 .Ping(47)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnFrameHeader(1, 25, DATA, 0));
  EXPECT_CALL(visitor, OnBeginDataForStream(1, 25));
  EXPECT_CALL(visitor, OnDataForStream(1, _)).WillOnce(testing::Return(false));
  EXPECT_CALL(visitor, OnConnectionError());

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(NGHTTP2_ERR_CALLBACK_FAILURE, result);

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  // Some bytes should have been serialized.
  EXPECT_EQ(0, send_result);
  // SETTINGS ack.
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
}

TEST(NgHttp2AdapterTest, ServerSubmitResponse) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  EXPECT_FALSE(adapter->want_write());

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "GET"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/true)
                                 .Serialize();
  testing::InSequence s;

  const char* kSentinel1 = "arbitrary pointer 1";

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());
  // Stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1))
      .WillOnce(testing::InvokeWithoutArgs([&adapter, kSentinel1]() {
        adapter->SetStreamUserData(1, const_cast<char*>(kSentinel1));
        return true;
      }));
  EXPECT_CALL(visitor, OnEndStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  EXPECT_EQ(1, adapter->GetHighestReceivedStreamId());

  // Server will want to send a SETTINGS ack.
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
  visitor.Clear();

  EXPECT_EQ(0, adapter->GetHpackEncoderDynamicTableSize());

  EXPECT_FALSE(adapter->want_write());
  const absl::string_view kBody = "This is an example response body.";
  // A data fin is not sent so that the stream remains open, and the flow
  // control state can be verified.
  auto body1 = absl::make_unique<TestDataFrameSource>(visitor, false);
  body1->AppendPayload(kBody);
  int submit_result = adapter->SubmitResponse(
      1,
      ToHeaders({{":status", "404"},
                 {"x-comment", "I have no idea what you're talking about."}}),
      std::move(body1));
  EXPECT_EQ(submit_result, 0);
  EXPECT_TRUE(adapter->want_write());

  // Stream user data should have been set successfully after receiving headers.
  EXPECT_EQ(kSentinel1, adapter->GetStreamUserData(1));
  adapter->SetStreamUserData(1, nullptr);
  EXPECT_EQ(nullptr, adapter->GetStreamUserData(1));

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, 1, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, 1, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, 1, _, 0x0, 0));

  send_result = adapter->Send();
  EXPECT_EQ(0, send_result);

  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  EXPECT_FALSE(adapter->want_write());

  // Some data was sent, so the remaining send window size should be less than
  // the default.
  EXPECT_LT(adapter->GetStreamSendWindowSize(1), kInitialFlowControlWindowSize);
  EXPECT_GT(adapter->GetStreamSendWindowSize(1), 0);
  // Send window for a nonexistent stream is not available.
  EXPECT_EQ(adapter->GetStreamSendWindowSize(3), -1);

  EXPECT_GT(adapter->GetHpackEncoderDynamicTableSize(), 0);
}

// Should also test: client attempts shutdown, server attempts shutdown after an
// explicit GOAWAY.
TEST(NgHttp2AdapterTest, ServerSendsShutdown) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "POST"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/false)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());

  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 4));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "POST"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  adapter->SubmitShutdownNotice();

  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(GOAWAY, 0, _, 0x0));
  EXPECT_CALL(visitor, OnFrameSent(GOAWAY, 0, _, 0x0, 0));

  int send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::GOAWAY}));
}

TEST(NgHttp2AdapterTest, ServerSendsTrailers) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  EXPECT_FALSE(adapter->want_write());

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "GET"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/true)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());
  // Stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnEndStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  // Server will want to send a SETTINGS ack.
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, 0, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, 0, 0x1, 0));

  int send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS}));
  visitor.Clear();

  EXPECT_FALSE(adapter->want_write());
  const absl::string_view kBody = "This is an example response body.";

  // The body source must indicate that the end of the body is not the end of
  // the stream.
  auto body1 = absl::make_unique<TestDataFrameSource>(visitor, false);
  body1->AppendPayload(kBody);
  body1->EndData();
  int submit_result = adapter->SubmitResponse(
      1, ToHeaders({{":status", "200"}, {"x-comment", "Sure, sounds good."}}),
      std::move(body1));
  EXPECT_EQ(submit_result, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, 1, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, 1, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, 1, _, 0x0, 0));

  send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  // The body source has been exhausted by the call to Send() above.
  int trailer_result = adapter->SubmitTrailer(
      1, ToHeaders({{"final-status", "a-ok"},
                    {"x-comment", "trailers sure are cool"}}));
  ASSERT_EQ(trailer_result, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, 1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, 1, _, 0x5, 0));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::NO_ERROR));

  send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS}));
}

TEST(NgHttp2AdapterTest, ClientSendsContinuation) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  EXPECT_FALSE(adapter->want_write());

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "GET"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/true,
                                          /*add_continuation=*/true)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());
  // Stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 1));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, CONTINUATION, 4));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnEndStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);
}

TEST(NgHttp2AdapterTest, ClientSendsMetadataWithContinuation) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  EXPECT_FALSE(adapter->want_write());

  const std::string frames =
      TestFrameSequence()
          .ClientPreface()
          .Metadata(0, "Example connection metadata in multiple frames", true)
          .Headers(1,
                   {{":method", "GET"},
                    {":scheme", "https"},
                    {":authority", "example.com"},
                    {":path", "/this/is/request/one"}},
                   /*fin=*/false,
                   /*add_continuation=*/true)
          .Metadata(1,
                    "Some stream metadata that's also sent in multiple frames",
                    true)
          .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());
  // Metadata on stream 0
  EXPECT_CALL(visitor, OnFrameHeader(0, _, kMetadataFrameType, 0));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnFrameHeader(0, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataForStream(0, _));
  EXPECT_CALL(visitor, OnMetadataEndForStream(0));

  // Stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 0));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, CONTINUATION, 4));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  // Metadata on stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, kMetadataFrameType, 0));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnFrameHeader(1, _, kMetadataFrameType, 4));
  EXPECT_CALL(visitor, OnBeginMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataForStream(1, _));
  EXPECT_CALL(visitor, OnMetadataEndForStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);
  EXPECT_EQ(TestFrameSequence::MetadataBlockForPayload(
                "Example connection metadata in multiple frames"),
            absl::StrJoin(visitor.GetMetadata(0), ""));
  EXPECT_EQ(TestFrameSequence::MetadataBlockForPayload(
                "Some stream metadata that's also sent in multiple frames"),
            absl::StrJoin(visitor.GetMetadata(1), ""));
}

TEST(NgHttp2AdapterTest, ServerSendsInvalidTrailers) {
  DataSavingVisitor visitor;
  auto adapter = NgHttp2Adapter::CreateServerAdapter(visitor);
  EXPECT_FALSE(adapter->want_write());

  const std::string frames = TestFrameSequence()
                                 .ClientPreface()
                                 .Headers(1,
                                          {{":method", "GET"},
                                           {":scheme", "https"},
                                           {":authority", "example.com"},
                                           {":path", "/this/is/request/one"}},
                                          /*fin=*/true)
                                 .Serialize();
  testing::InSequence s;

  // Client preface (empty SETTINGS)
  EXPECT_CALL(visitor, OnFrameHeader(0, 0, SETTINGS, 0));
  EXPECT_CALL(visitor, OnSettingsStart());
  EXPECT_CALL(visitor, OnSettingsEnd());
  // Stream 1
  EXPECT_CALL(visitor, OnFrameHeader(1, _, HEADERS, 5));
  EXPECT_CALL(visitor, OnBeginHeadersForStream(1));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":method", "GET"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":scheme", "https"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":authority", "example.com"));
  EXPECT_CALL(visitor, OnHeaderForStream(1, ":path", "/this/is/request/one"));
  EXPECT_CALL(visitor, OnEndHeadersForStream(1));
  EXPECT_CALL(visitor, OnEndStream(1));

  const int64_t result = adapter->ProcessBytes(frames);
  EXPECT_EQ(frames.size(), result);

  const absl::string_view kBody = "This is an example response body.";

  // The body source must indicate that the end of the body is not the end of
  // the stream.
  auto body1 = absl::make_unique<TestDataFrameSource>(visitor, false);
  body1->AppendPayload(kBody);
  body1->EndData();
  int submit_result = adapter->SubmitResponse(
      1, ToHeaders({{":status", "200"}, {"x-comment", "Sure, sounds good."}}),
      std::move(body1));
  EXPECT_EQ(submit_result, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(SETTINGS, 0, _, 0x1));
  EXPECT_CALL(visitor, OnFrameSent(SETTINGS, 0, _, 0x1, 0));
  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, 1, _, 0x4));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, 1, _, 0x4, 0));
  EXPECT_CALL(visitor, OnFrameSent(DATA, 1, _, 0x0, 0));

  int send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::SETTINGS,
                                            spdy::SpdyFrameType::HEADERS,
                                            spdy::SpdyFrameType::DATA}));
  EXPECT_THAT(visitor.data(), testing::HasSubstr(kBody));
  visitor.Clear();
  EXPECT_FALSE(adapter->want_write());

  // The body source has been exhausted by the call to Send() above.
  int trailer_result =
      adapter->SubmitTrailer(1, ToHeaders({{":final-status", "a-ok"}}));
  ASSERT_EQ(trailer_result, 0);
  EXPECT_TRUE(adapter->want_write());

  EXPECT_CALL(visitor, OnBeforeFrameSent(HEADERS, 1, _, 0x5));
  EXPECT_CALL(visitor, OnFrameSent(HEADERS, 1, _, 0x5, 0));
  EXPECT_CALL(visitor, OnCloseStream(1, Http2ErrorCode::NO_ERROR));

  send_result = adapter->Send();
  EXPECT_EQ(0, send_result);
  EXPECT_THAT(visitor.data(), EqualsFrames({spdy::SpdyFrameType::HEADERS}));
}

}  // namespace
}  // namespace test
}  // namespace adapter
}  // namespace http2