Add QuicDataChannel and QuicDataTransport classes

webrtc/api/quicdatachannel_unittest.cc

Index: webrtc/api/quicdatachannel_unittest.cc
diff --git a/webrtc/api/quicdatachannel_unittest.cc b/webrtc/api/quicdatachannel_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2dd91024d0c0b841d1119eb3080420780f883a5e
--- /dev/null
+++ b/webrtc/api/quicdatachannel_unittest.cc
@@ -0,0 +1,659 @@
+/*
+ *  Copyright 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/api/quicdatachannel.h"
+
+#include <map>
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "webrtc/base/bind.h"
+#include "webrtc/base/gunit.h"
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/p2p/base/faketransportcontroller.h"
+#include "webrtc/p2p/quic/quictransportchannel.h"
+#include "webrtc/p2p/quic/reliablequicstream.h"
+
+using cricket::FakeTransportChannel;
+using cricket::QuicTransportChannel;
+using cricket::ReliableQuicStream;
+
+using webrtc::DataBuffer;
+using webrtc::DataChannelObserver;
+using webrtc::DataChannelInit;
+using webrtc::QuicDataChannel;
+
+namespace {
+
+// Timeout for asynchronous operations.
+static const int kTimeoutMs = 1000;  // milliseconds
+
+// Small messages that can be sent within a single QUIC packet.
+static const std::string kSmallMessage1 = "Hello, world!";
+static const std::string kSmallMessage2 = "WebRTC";
+static const std::string kSmallMessage3 = "1";
+static const std::string kSmallMessage4 = "abcdefghijklmnopqrstuvwxyz";
+static const DataBuffer kSmallBuffer1(kSmallMessage1);
+static const DataBuffer kSmallBuffer2(kSmallMessage2);
+static const DataBuffer kSmallBuffer3(kSmallMessage3);
+static const DataBuffer kSmallBuffer4(kSmallMessage4);
+
+// Large messages (> 1350 bytes) that exceed the max size of a QUIC packet.
+// These are < 16 KB so they don't exceed the QUIC stream flow control limit.
+static const std::string kLargeMessage1 = std::string("a", 2000);
+static const std::string kLargeMessage2 = std::string("a", 4000);
+static const std::string kLargeMessage3 = std::string("a", 8000);
+static const std::string kLargeMessage4 = std::string("a", 12000);
+static const DataBuffer kLargeBuffer1(kLargeMessage1);
+static const DataBuffer kLargeBuffer2(kLargeMessage2);
+static const DataBuffer kLargeBuffer3(kLargeMessage3);
+static const DataBuffer kLargeBuffer4(kLargeMessage4);
+
+// Oversized message (> 16 KB) that violates the QUIC stream flow control limit.
+static const std::string kOversizedMessage = std::string("a", 20000);
+static const DataBuffer kOversizedBuffer(kOversizedMessage);
+
+// Creates a fingerprint from a certificate.
+static rtc::SSLFingerprint* CreateFingerprint(rtc::RTCCertificate* cert) {
+  std::string digest_algorithm;
+  cert->ssl_certificate().GetSignatureDigestAlgorithm(&digest_algorithm);
+  rtc::scoped_ptr<rtc::SSLFingerprint> fingerprint(
+      rtc::SSLFingerprint::Create(digest_algorithm, cert->identity()));
+  return fingerprint.release();
+}
+
+// FakeObserver receives messages from the QuicDataChannel.
+class FakeObserver : public DataChannelObserver {
+ public:
+  FakeObserver()
+      : on_state_change_count_(0), on_buffered_amount_change_count_(0) {}
+
+  // DataChannelObserver overrides.
+  void OnStateChange() override { ++on_state_change_count_; }
+  void OnBufferedAmountChange(uint64_t previous_amount) override {
+    ++on_buffered_amount_change_count_;
+  }
+  void OnMessage(const webrtc::DataBuffer& buffer) override {
+    messages_.push_back(std::string(buffer.data.data<char>(), buffer.size()));
+  }
+
+  const std::vector<std::string>& messages() const { return messages_; }
+
+  size_t messages_received() const { return messages_.size(); }
+
+  size_t on_state_change_count() const { return on_state_change_count_; }
+
+  size_t on_buffered_amount_change_count() const {
+    return on_buffered_amount_change_count_;
+  }
+
+ private:
+  std::vector<std::string> messages_;
+  size_t on_state_change_count_;
+  size_t on_buffered_amount_change_count_;
+};
+
+// FakeQuicDataTransport simulates QuicDataTransport by dispatching QUIC
+// stream messages to data channels and encoding/decoding messages.
+class FakeQuicDataTransport : public sigslot::has_slots<> {
+ public:
+  FakeQuicDataTransport() {}
+
+  void ConnectToTransportChannel(QuicTransportChannel* quic_transport_channel) {
+    quic_transport_channel->SignalIncomingStream.connect(
+        this, &FakeQuicDataTransport::OnIncomingStream);
+  }
+
+  rtc::scoped_refptr<QuicDataChannel> CreateDataChannel(
+      int id,
+      const std::string& label,
+      const std::string& protocol) {
+    DataChannelInit config;
+    config.id = id;
+    config.protocol = protocol;
+    rtc::scoped_refptr<QuicDataChannel> data_channel(new QuicDataChannel(
+        rtc::Thread::Current(), rtc::Thread::Current(), label, config));
+    data_channel_by_id_[id] = data_channel;
+    return data_channel;
+  }
+
+ private:
+  void OnIncomingStream(cricket::ReliableQuicStream* stream) {
+    incoming_stream_ = stream;
+    incoming_stream_->SignalDataReceived.connect(
+        this, &FakeQuicDataTransport::OnDataReceived);
+  }
+
+  void OnDataReceived(net::QuicStreamId id, const char* data, size_t len) {
+    ASSERT_EQ(incoming_stream_->id(), id);
+    incoming_stream_->SignalDataReceived.disconnect(this);
+    // Retrieve the data channel ID and message ID.
+    int data_channel_id;
+    uint64_t message_id;
+    size_t bytes_read;
+    ASSERT_TRUE(webrtc::ParseQuicDataMessageHeader(data, len, &data_channel_id,
+                                                   &message_id, &bytes_read));
+    data += bytes_read;
+    len -= bytes_read;
+    // Dispatch the message to the matching QuicDataChannel.
+    const auto& kv = data_channel_by_id_.find(data_channel_id);
+    ASSERT_NE(kv, data_channel_by_id_.end());
+    QuicDataChannel* data_channel = kv->second;
+    QuicDataChannel::Message message;
+    message.id = message_id;
+    message.buffer = rtc::CopyOnWriteBuffer(data, len);
+    message.stream = incoming_stream_;
+    data_channel->OnIncomingMessage(std::move(message));
+    incoming_stream_ = nullptr;
+  }
+
+  // Map of data channel ID => QuicDataChannel.
+  std::map<int, rtc::scoped_refptr<QuicDataChannel>> data_channel_by_id_;
+  // Last incoming QUIC stream which has arrived.
+  cricket::ReliableQuicStream* incoming_stream_ = nullptr;
+};
+
+// A peer who creates a QuicDataChannel to transfer data, and simulates network
+// connectivity with a fake ICE channel wrapped by the QUIC transport channel.
+class QuicDataChannelPeer {
+ public:
+  QuicDataChannelPeer()
+      : ice_transport_channel_("data", 0),
+        quic_transport_channel_(&ice_transport_channel_) {
+    ice_transport_channel_.SetAsync(true);
+    fake_quic_data_transport_.ConnectToTransportChannel(
+        &quic_transport_channel_);
+  }
+
+  void GenerateCertificateAndFingerprint() {
+    rtc::scoped_refptr<rtc::RTCCertificate> local_cert =
+        rtc::RTCCertificate::Create(rtc::scoped_ptr<rtc::SSLIdentity>(
+            rtc::SSLIdentity::Generate("cert_name", rtc::KT_DEFAULT)));
+    quic_transport_channel_.SetLocalCertificate(local_cert);
+    local_fingerprint_.reset(CreateFingerprint(local_cert.get()));
+  }
+
+  rtc::scoped_refptr<QuicDataChannel> CreateDataChannelWithTransportChannel(
+      int id,
+      const std::string& label,
+      const std::string& protocol) {
+    rtc::scoped_refptr<QuicDataChannel> data_channel =
+        fake_quic_data_transport_.CreateDataChannel(id, label, protocol);
+    data_channel->SetTransportChannel(&quic_transport_channel_);
+    return data_channel;
+  }
+
+  rtc::scoped_refptr<QuicDataChannel> CreateDataChannelWithoutTransportChannel(
+      int id,
+      const std::string& label,
+      const std::string& protocol) {
+    return fake_quic_data_transport_.CreateDataChannel(id, label, protocol);
+  }
+
+  // Connects |ice_transport_channel_| to that of the other peer.
+  void Connect(QuicDataChannelPeer* other_peer) {
+    ice_transport_channel_.Connect();
+    other_peer->ice_transport_channel_.Connect();
+    ice_transport_channel_.SetDestination(&other_peer->ice_transport_channel_);
+  }
+
+  rtc::scoped_ptr<rtc::SSLFingerprint>& local_fingerprint() {
+    return local_fingerprint_;
+  }
+
+  QuicTransportChannel* quic_transport_channel() {
+    return &quic_transport_channel_;
+  }
+
+  FakeTransportChannel* ice_transport_channel() {
+    return &ice_transport_channel_;
+  }
+
+ private:
+  FakeTransportChannel ice_transport_channel_;
+  QuicTransportChannel quic_transport_channel_;
+
+  rtc::scoped_ptr<rtc::SSLFingerprint> local_fingerprint_;
+
+  FakeQuicDataTransport fake_quic_data_transport_;
+};
+
+class QuicDataChannelTest : public testing::Test {
+ public:
+  QuicDataChannelTest() {}
+
+  // Connect the QuicTransportChannels and complete the crypto handshake.
+  void ConnectTransportChannels() {
+    SetCryptoParameters();
+    peer1_.Connect(&peer2_);
+    ASSERT_TRUE_WAIT(peer1_.quic_transport_channel()->writable() &&
+                         peer2_.quic_transport_channel()->writable(),
+                     kTimeoutMs);
+  }
+
+  // Sets crypto parameters required for the QUIC handshake.
+  void SetCryptoParameters() {
+    peer1_.GenerateCertificateAndFingerprint();
+    peer2_.GenerateCertificateAndFingerprint();
+
+    peer1_.quic_transport_channel()->SetSslRole(rtc::SSL_CLIENT);
+    peer2_.quic_transport_channel()->SetSslRole(rtc::SSL_SERVER);
+
+    rtc::scoped_ptr<rtc::SSLFingerprint>& peer1_fingerprint =
+        peer1_.local_fingerprint();
+    rtc::scoped_ptr<rtc::SSLFingerprint>& peer2_fingerprint =
+        peer2_.local_fingerprint();
+
+    peer1_.quic_transport_channel()->SetRemoteFingerprint(
+        peer2_fingerprint->algorithm,
+        reinterpret_cast<const uint8_t*>(peer2_fingerprint->digest.data()),
+        peer2_fingerprint->digest.size());
+    peer2_.quic_transport_channel()->SetRemoteFingerprint(
+        peer1_fingerprint->algorithm,
+        reinterpret_cast<const uint8_t*>(peer1_fingerprint->digest.data()),
+        peer1_fingerprint->digest.size());
+  }
+
+ protected:
+  QuicDataChannelPeer peer1_;
+  QuicDataChannelPeer peer2_;
+};
+
+// Tests that a QuicDataChannel transitions from connecting to open when
+// the QuicTransportChannel becomes writable for the first time.
+TEST_F(QuicDataChannelTest, DataChannelOpensWhenTransportChannelConnects) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(4, "label", "protocol");
+  EXPECT_EQ(webrtc::DataChannelInterface::kConnecting, data_channel->state());
+  ConnectTransportChannels();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kOpen, data_channel->state(),
+                 kTimeoutMs);
+}
+
+// Tests that a QuicDataChannel transitions from connecting to open when
+// SetTransportChannel is called with a QuicTransportChannel that is already
+// writable.
+TEST_F(QuicDataChannelTest, DataChannelOpensWhenTransportChannelWritable) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithoutTransportChannel(4, "label", "protocol");
+  ConnectTransportChannels();
+  EXPECT_EQ(webrtc::DataChannelInterface::kConnecting, data_channel->state());
+  data_channel->SetTransportChannel(peer1_.quic_transport_channel());
+  EXPECT_EQ(webrtc::DataChannelInterface::kOpen, data_channel->state());
+}
+
+// Tests that the QuicDataChannel transfers messages small enough to fit into a
+// single QUIC stream frame.
+TEST_F(QuicDataChannelTest, TransferSmallMessage) {
+  ConnectTransportChannels();
+  int data_channel_id = 2;
+  std::string label = "label";
+  std::string protocol = "protocol";
+  rtc::scoped_refptr<QuicDataChannel> peer1_data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer1_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+  rtc::scoped_refptr<QuicDataChannel> peer2_data_channel =
+      peer2_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer2_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+
+  FakeObserver peer1_observer;
+  peer1_data_channel->RegisterObserver(&peer1_observer);
+  FakeObserver peer2_observer;
+  peer2_data_channel->RegisterObserver(&peer2_observer);
+
+  // peer1 -> peer2
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer1));
+  ASSERT_EQ_WAIT(1, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kSmallMessage1, peer2_observer.messages()[0]);
+  // peer2 -> peer1
+  EXPECT_TRUE(peer2_data_channel->Send(kSmallBuffer2));
+  ASSERT_EQ_WAIT(1, peer1_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kSmallMessage2, peer1_observer.messages()[0]);
+  // peer2 -> peer1
+  EXPECT_TRUE(peer2_data_channel->Send(kSmallBuffer3));
+  ASSERT_EQ_WAIT(2, peer1_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kSmallMessage3, peer1_observer.messages()[1]);
+  // peer1 -> peer2
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer4));
+  ASSERT_EQ_WAIT(2, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kSmallMessage4, peer2_observer.messages()[1]);
+}
+
+// Tests that QuicDataChannel transfers messages large enough to fit into
+// multiple QUIC stream frames, which don't violate the QUIC flow control limit.
+// These require buffering by the QuicDataChannel.
+TEST_F(QuicDataChannelTest, TransferLargeMessage) {
+  ConnectTransportChannels();
+  int data_channel_id = 347;
+  std::string label = "label";
+  std::string protocol = "protocol";
+  rtc::scoped_refptr<QuicDataChannel> peer1_data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer1_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+  rtc::scoped_refptr<QuicDataChannel> peer2_data_channel =
+      peer2_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer2_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+
+  FakeObserver peer1_observer;
+  peer1_data_channel->RegisterObserver(&peer1_observer);
+  FakeObserver peer2_observer;
+  peer2_data_channel->RegisterObserver(&peer2_observer);
+
+  // peer1 -> peer2
+  EXPECT_TRUE(peer1_data_channel->Send(kLargeBuffer1));
+  ASSERT_TRUE_WAIT(peer2_observer.messages_received() == 1, kTimeoutMs);
+  EXPECT_EQ(kLargeMessage1, peer2_observer.messages()[0]);
+  // peer2 -> peer1
+  EXPECT_TRUE(peer2_data_channel->Send(kLargeBuffer2));
+  ASSERT_EQ_WAIT(1, peer1_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kLargeMessage2, peer1_observer.messages()[0]);
+  // peer2 -> peer1
+  EXPECT_TRUE(peer2_data_channel->Send(kLargeBuffer3));
+  ASSERT_EQ_WAIT(2, peer1_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kLargeMessage3, peer1_observer.messages()[1]);
+  // peer1 -> peer2
+  EXPECT_TRUE(peer1_data_channel->Send(kLargeBuffer4));
+  ASSERT_EQ_WAIT(2, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kLargeMessage4, peer2_observer.messages()[1]);
+}
+
+// Tests that when a message size exceeds the flow control limit (> 16KB), the
+// QuicDataChannel can queue the data and send it after receiving window update
+// frames from the remote peer.
+TEST_F(QuicDataChannelTest, TransferOversizedMessage) {
+  ConnectTransportChannels();
+  int data_channel_id = 189;
+  std::string label = "label";
+  std::string protocol = "protocol";
+  rtc::scoped_refptr<QuicDataChannel> peer1_data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  rtc::scoped_refptr<QuicDataChannel> peer2_data_channel =
+      peer2_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer2_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+
+  FakeObserver peer1_observer;
+  peer1_data_channel->RegisterObserver(&peer1_observer);
+  FakeObserver peer2_observer;
+  peer2_data_channel->RegisterObserver(&peer2_observer);
+
+  EXPECT_TRUE(peer1_data_channel->Send(kOversizedBuffer));
+  EXPECT_EQ(1, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_EQ_WAIT(1, peer2_data_channel->GetNumIncomingStreams(), kTimeoutMs);
+  ASSERT_EQ_WAIT(1, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(kOversizedMessage, peer2_observer.messages()[0]);
+  EXPECT_EQ(0, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_EQ(0, peer2_data_channel->GetNumIncomingStreams());
+}
+
+// Tests that empty messages can be sent.
+TEST_F(QuicDataChannelTest, TransferEmptyMessage) {
+  ConnectTransportChannels();
+  int data_channel_id = 69;
+  std::string label = "label";
+  std::string protocol = "protocol";
+  rtc::scoped_refptr<QuicDataChannel> peer1_data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  rtc::scoped_refptr<QuicDataChannel> peer2_data_channel =
+      peer2_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer2_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+
+  FakeObserver peer1_observer;
+  peer1_data_channel->RegisterObserver(&peer1_observer);
+  FakeObserver peer2_observer;
+  peer2_data_channel->RegisterObserver(&peer2_observer);
+
+  EXPECT_TRUE(peer1_data_channel->Send(DataBuffer("")));
+  ASSERT_EQ_WAIT(1, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ("", peer2_observer.messages()[0]);
+}
+
+// Tests that when the QuicDataChannel is open and sends a message while the
+// QuicTransportChannel is unwritable, it gets buffered then received once the
+// QuicTransportChannel becomes writable again.
+TEST_F(QuicDataChannelTest, MessagesReceivedWhenTransportChannelReconnects) {
+  ConnectTransportChannels();
+  int data_channel_id = 401;
+  std::string label = "label";
+  std::string protocol = "protocol";
+  rtc::scoped_refptr<QuicDataChannel> peer1_data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer1_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+  rtc::scoped_refptr<QuicDataChannel> peer2_data_channel =
+      peer2_.CreateDataChannelWithTransportChannel(data_channel_id, label,
+                                                   protocol);
+  ASSERT_TRUE(peer2_data_channel->state() ==
+              webrtc::DataChannelInterface::kOpen);
+
+  FakeObserver peer1_observer;
+  peer1_data_channel->RegisterObserver(&peer1_observer);
+  FakeObserver peer2_observer;
+  peer2_data_channel->RegisterObserver(&peer2_observer);
+  // writable => unwritable
+  peer1_.ice_transport_channel()->SetWritable(false);
+  ASSERT_FALSE(peer1_.quic_transport_channel()->writable());
+  // Verify that sent data is buffered.
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer1));
+  EXPECT_EQ(1, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer2));
+  EXPECT_EQ(2, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer3));
+  EXPECT_EQ(3, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_TRUE(peer1_data_channel->Send(kSmallBuffer4));
+  EXPECT_EQ(4, peer1_data_channel->GetNumWriteBlockedStreams());
+  // unwritable => writable
+  peer1_.ice_transport_channel()->SetWritable(true);
+  ASSERT_TRUE(peer1_.quic_transport_channel()->writable());
+  ASSERT_EQ_WAIT(4, peer2_observer.messages_received(), kTimeoutMs);
+  EXPECT_EQ(0, peer1_data_channel->GetNumWriteBlockedStreams());
+  EXPECT_EQ(0, peer2_data_channel->GetNumIncomingStreams());
+}
+
+// Tests that the QuicDataChannel does not send before it is open.
+TEST_F(QuicDataChannelTest, TransferMessageBeforeChannelOpens) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(6, "label", "protocol");
+  ASSERT_TRUE(data_channel->state() ==
+              webrtc::DataChannelInterface::kConnecting);
+  EXPECT_FALSE(data_channel->Send(kSmallBuffer1));
+}
+
+// Tests that the QuicDataChannel does not send after it is closed.
+TEST_F(QuicDataChannelTest, TransferDataAfterChannelClosed) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(42, "label", "protocol");
+  data_channel->Close();
+  ASSERT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+  EXPECT_FALSE(data_channel->Send(kSmallBuffer1));
+}
+
+// Tests that QuicDataChannel state changes fire OnStateChanged() for the
+// observer, with the correct data channel states, when the data channel
+// transitions from kConnecting => kOpen => kClosing => kClosed.
+TEST_F(QuicDataChannelTest, OnStateChangedFired) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(7, "label", "protocol");
+  FakeObserver observer;
+  data_channel->RegisterObserver(&observer);
+  EXPECT_EQ(webrtc::DataChannelInterface::kConnecting, data_channel->state());
+  EXPECT_EQ(0, observer.on_state_change_count());
+  ConnectTransportChannels();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kOpen, data_channel->state(),
+                 kTimeoutMs);
+  EXPECT_EQ(1, observer.on_state_change_count());
+  data_channel->Close();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+  // 2 state changes due to kClosing and kClosed.
+  EXPECT_EQ(3, observer.on_state_change_count());
+}
+
+// Tests that a QuicTransportChannel can be closed without being opened when it
+// is connected to a transprot chanenl.
+TEST_F(QuicDataChannelTest, NeverOpenedWithTransportChannel) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(7, "label", "protocol");
+  EXPECT_EQ(webrtc::DataChannelInterface::kConnecting, data_channel->state());
+  data_channel->Close();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+}
+
+// Tests that a QuicTransportChannel can be closed without being opened or
+// connected to a transport channel.
+TEST_F(QuicDataChannelTest, NeverOpenedWithoutTransportChannel) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithoutTransportChannel(7, "label", "protocol");
+  EXPECT_EQ(webrtc::DataChannelInterface::kConnecting, data_channel->state());
+  data_channel->Close();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+}
+
+// Tests that the QuicDataChannel is closed when the QUIC connection closes.
+TEST_F(QuicDataChannelTest, ClosedOnTransportError) {
+  ConnectTransportChannels();
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(1, "label", "protocol");
+  EXPECT_EQ(webrtc::DataChannelInterface::kOpen, data_channel->state());
+  ReliableQuicStream* stream =
+      peer1_.quic_transport_channel()->CreateQuicStream();
+  ASSERT_NE(nullptr, stream);
+  stream->CloseConnectionWithDetails(net::QuicErrorCode::QUIC_NO_ERROR,
+                                     "Closing QUIC for testing");
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+}
+
+// Tests that an already closed QuicDataChannel does not fire onStateChange and
+// remains closed.
+TEST_F(QuicDataChannelTest, DoesNotChangeStateWhenClosed) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(4, "label", "protocol");
+  FakeObserver observer;
+  data_channel->RegisterObserver(&observer);
+  data_channel->Close();
+  EXPECT_EQ_WAIT(webrtc::DataChannelInterface::kClosed, data_channel->state(),
+                 kTimeoutMs);
+  // OnStateChange called for kClosing and kClosed.
+  EXPECT_EQ(2, observer.on_state_change_count());
+  // Call Close() again to verify that the state cannot be kClosing.
+  data_channel->Close();
+  EXPECT_EQ(webrtc::DataChannelInterface::kClosed, data_channel->state());
+  EXPECT_EQ(2, observer.on_state_change_count());
+  ConnectTransportChannels();
+  EXPECT_EQ(webrtc::DataChannelInterface::kClosed, data_channel->state());
+  EXPECT_EQ(2, observer.on_state_change_count());
+  // writable => unwritable
+  peer1_.ice_transport_channel()->SetWritable(false);
+  ASSERT_FALSE(peer1_.quic_transport_channel()->writable());
+  EXPECT_EQ(webrtc::DataChannelInterface::kClosed, data_channel->state());
+  EXPECT_EQ(2, observer.on_state_change_count());
+  // unwritable => writable
+  peer1_.ice_transport_channel()->SetWritable(true);
+  ASSERT_TRUE(peer1_.quic_transport_channel()->writable());
+  EXPECT_EQ(webrtc::DataChannelInterface::kClosed, data_channel->state());
+  EXPECT_EQ(2, observer.on_state_change_count());
+}
+
+// Tests that when the QuicDataChannel is open and the QuicTransportChannel
+// transitions between writable and unwritable, it does not fire onStateChange
+// and remains open.
+TEST_F(QuicDataChannelTest, DoesNotChangeStateWhenTransportChannelReconnects) {
+  ConnectTransportChannels();
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(4, "label", "protocol");
+  FakeObserver observer;
+  data_channel->RegisterObserver(&observer);
+  EXPECT_EQ(webrtc::DataChannelInterface::kOpen, data_channel->state());
+  EXPECT_EQ(0, observer.on_state_change_count());
+  // writable => unwritable
+  peer1_.ice_transport_channel()->SetWritable(false);
+  ASSERT_FALSE(peer1_.quic_transport_channel()->writable());
+  EXPECT_EQ(webrtc::DataChannelInterface::kOpen, data_channel->state());
+  EXPECT_EQ(0, observer.on_state_change_count());
+  // unwritable => writable
+  peer1_.ice_transport_channel()->SetWritable(true);
+  ASSERT_TRUE(peer1_.quic_transport_channel()->writable());
+  EXPECT_EQ(webrtc::DataChannelInterface::kOpen, data_channel->state());
+  EXPECT_EQ(0, observer.on_state_change_count());
+}
+
+// Tests that SetTransportChannel returns false when setting a NULL transport
+// channel or a transport channel that is not equivalent to the one already set.
+TEST_F(QuicDataChannelTest, SetTransportChannelReturnValue) {
+  rtc::scoped_refptr<QuicDataChannel> data_channel =
+      peer1_.CreateDataChannelWithTransportChannel(4, "label", "protocol");
+  EXPECT_FALSE(data_channel->SetTransportChannel(nullptr));
+  QuicTransportChannel* transport_channel = peer1_.quic_transport_channel();
+  EXPECT_TRUE(data_channel->SetTransportChannel(transport_channel));
+  EXPECT_TRUE(data_channel->SetTransportChannel(transport_channel));
+  QuicTransportChannel* other_transport_channel =
+      peer2_.quic_transport_channel();
+  EXPECT_FALSE(data_channel->SetTransportChannel(other_transport_channel));
+}
+
+// Tests that the QUIC message header is encoded with the correct number of
+// bytes and is properly decoded.
+TEST_F(QuicDataChannelTest, EncodeParseQuicDataMessageHeader) {
+  int data_channel_id1 = 127;  // 1 byte
+  uint64_t message_id1 = 0;    // 1 byte
+  rtc::CopyOnWriteBuffer header1;
+  webrtc::WriteQuicDataChannelMessageHeader(data_channel_id1, message_id1,
+                                            &header1);
+  EXPECT_EQ(2u, header1.size());
+
+  int decoded_data_channel_id1;
+  uint64_t decoded_message_id1;
+  size_t bytes_read1;
+  ASSERT_TRUE(webrtc::ParseQuicDataMessageHeader(
+      header1.data<char>(), header1.size(), &decoded_data_channel_id1,
+      &decoded_message_id1, &bytes_read1));
+  EXPECT_EQ(data_channel_id1, decoded_data_channel_id1);
+  EXPECT_EQ(message_id1, decoded_message_id1);
+  EXPECT_EQ(2u, bytes_read1);
+
+  int data_channel_id2 = 4178;           // 2 bytes
+  uint64_t message_id2 = 1324921792003;  // 6 bytes
+  rtc::CopyOnWriteBuffer header2;
+  webrtc::WriteQuicDataChannelMessageHeader(data_channel_id2, message_id2,
+                                            &header2);
+  EXPECT_EQ(8u, header2.size());
+
+  int decoded_data_channel_id2;
+  uint64_t decoded_message_id2;
+  size_t bytes_read2;
+  ASSERT_TRUE(webrtc::ParseQuicDataMessageHeader(
+      header2.data<char>(), header2.size(), &decoded_data_channel_id2,
+      &decoded_message_id2, &bytes_read2));
+  EXPECT_EQ(data_channel_id2, decoded_data_channel_id2);
+  EXPECT_EQ(message_id2, decoded_message_id2);
+  EXPECT_EQ(8u, bytes_read2);
+}
+
+}  // namespace