TransportController refactoring

webrtc/p2p/base/transportcontroller_unittest.cc

+/*
+ *  Copyright 2015 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 <map>
+
+#include "webrtc/base/fakesslidentity.h"
+#include "webrtc/base/gunit.h"
+#include "webrtc/base/helpers.h"
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/base/sslidentity.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/p2p/base/dtlstransportchannel.h"
+#include "webrtc/p2p/base/faketransportcontroller.h"
+#include "webrtc/p2p/base/p2ptransportchannel.h"
+#include "webrtc/p2p/base/portallocator.h"
+#include "webrtc/p2p/base/transportcontroller.h"
+#include "webrtc/p2p/client/fakeportallocator.h"
+
+static const int kTimeout = 100;
+static const char kIceUfrag1[] = "TESTICEUFRAG0001";
+static const char kIcePwd1[] = "TESTICEPWD00000000000001";
+static const char kIceUfrag2[] = "TESTICEUFRAG0002";
+static const char kIcePwd2[] = "TESTICEPWD00000000000002";
+
+using cricket::Candidate;
+using cricket::Candidates;
+using cricket::FakeTransportChannel;
+using cricket::FakeTransportController;
+using cricket::IceConnectionState;
+using cricket::IceGatheringState;
+using cricket::TransportChannel;
+using cricket::TransportController;
+using cricket::TransportDescription;
+using cricket::TransportStats;
+
+// Only subclassing from FakeTransportController because currently that's the
+// only way to have a TransportController with fake TransportChannels.
+//
+// TODO(deadbeef): Change this once the Transport/TransportChannel class
+// heirarchy is cleaned up, and we can pass a "TransportChannelFactory" or
+// something similar into TransportController.
+typedef FakeTransportController TransportControllerForTest;
+
+class TransportControllerTest : public testing::Test,
+                                public sigslot::has_slots<> {
+ public:
+  TransportControllerTest()
+      : transport_controller_(new TransportControllerForTest()),
+        signaling_thread_(rtc::Thread::Current()) {
+    ConnectTransportControllerSignals();
+  }
+
+  void CreateTransportControllerWithWorkerThread() {
+    if (!worker_thread_) {
+      worker_thread_.reset(new rtc::Thread());
+      worker_thread_->Start();
+    }
+    transport_controller_.reset(
+        new TransportControllerForTest(worker_thread_.get()));
+    ConnectTransportControllerSignals();
+  }
+
+  void ConnectTransportControllerSignals() {
+    transport_controller_->SignalConnectionState.connect(
+        this, &TransportControllerTest::OnConnectionState);
+    transport_controller_->SignalReceiving.connect(
+        this, &TransportControllerTest::OnReceiving);
+    transport_controller_->SignalGatheringState.connect(
+        this, &TransportControllerTest::OnGatheringState);
+    transport_controller_->SignalCandidatesGathered.connect(
+        this, &TransportControllerTest::OnCandidatesGathered);
+  }
+
+  FakeTransportChannel* CreateChannel(const std::string& content,
+                                      int component) {
+    TransportChannel* channel =
+        transport_controller_->CreateTransportChannel_w(content, component);
+    return static_cast<FakeTransportChannel*>(channel);
+  }
+
+  void DestroyChannel(const std::string& content, int component) {
+    transport_controller_->DestroyTransportChannel_w(content, component);
+  }
+
+  Candidate CreateCandidate(int component) {
+    Candidate c;
+    c.set_address(rtc::SocketAddress("192.168.1.1", 8000));
+    c.set_component(1);
+    c.set_protocol(cricket::UDP_PROTOCOL_NAME);
+    c.set_priority(1);
+    return c;
+  }
+
+  // Used for thread hopping test.
+  void CreateChannelsAndCompleteConnectionOnWorkerThread() {
+    worker_thread_->Invoke<void>(rtc::Bind(
+        &TransportControllerTest::CreateChannelsAndCompleteConnection_w, this));
+  }
+
+  void CreateChannelsAndCompleteConnection_w() {
+    transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+    FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+    ASSERT_NE(nullptr, channel1);
+    FakeTransportChannel* channel2 = CreateChannel("video", 1);
+    ASSERT_NE(nullptr, channel2);
+
+    TransportDescription local_desc(
+        std::vector<std::string>(), kIceUfrag1, kIcePwd1, cricket::ICEMODE_FULL,
+        cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+    std::string err;
+    transport_controller_->SetLocalTransportDescription(
+        "audio", local_desc, cricket::CA_OFFER, &err);
+    transport_controller_->SetLocalTransportDescription(
+        "video", local_desc, cricket::CA_OFFER, &err);
+    channel1->SignalCandidateGathered(channel1, CreateCandidate(1));
+    channel2->SignalCandidateGathered(channel2, CreateCandidate(1));
+    channel1->SetCandidatesGatheringComplete();
+    channel2->SetCandidatesGatheringComplete();
+    channel1->SetConnectionCount(2);
+    channel2->SetConnectionCount(2);
+    channel1->SetReceiving(true);
+    channel2->SetReceiving(true);
+    channel1->SetWritable(true);
+    channel2->SetWritable(true);
+    channel1->SetConnectionCount(1);
+    channel2->SetConnectionCount(1);
+  }
+
+ protected:
+  void OnConnectionState(IceConnectionState state) {
+    if (!signaling_thread_->IsCurrent()) {
+      signaled_on_non_signaling_thread_ = true;
+    }
+    connection_state_ = state;
+    ++connection_state_signal_count_;
+  }
+
+  void OnReceiving(bool receiving) {
+    if (!signaling_thread_->IsCurrent()) {
+      signaled_on_non_signaling_thread_ = true;
+    }
+    receiving_ = receiving;
+    ++receiving_signal_count_;
+  }
+
+  void OnGatheringState(IceGatheringState state) {
+    if (!signaling_thread_->IsCurrent()) {
+      signaled_on_non_signaling_thread_ = true;
+    }
+    gathering_state_ = state;
+    ++gathering_state_signal_count_;
+  }
+
+  void OnCandidatesGathered(const std::string& transport_name,
+                            const Candidates& candidates) {
+    if (!signaling_thread_->IsCurrent()) {
+      signaled_on_non_signaling_thread_ = true;
+    }
+    candidates_[transport_name].insert(candidates_[transport_name].end(),
+                                       candidates.begin(), candidates.end());
+    ++candidates_signal_count_;
+  }
+
+  rtc::scoped_ptr<rtc::Thread> worker_thread_;  // Not used for most tests.
+  rtc::scoped_ptr<TransportControllerForTest> transport_controller_;
+
+  // Information received from signals from transport controller.
+  IceConnectionState connection_state_ = cricket::kIceConnectionConnecting;
+  bool receiving_ = false;
+  IceGatheringState gathering_state_ = cricket::kIceGatheringNew;
+  // transport_name => candidates
+  std::map<std::string, Candidates> candidates_;
+  // Counts of each signal emitted.
+  int connection_state_signal_count_ = 0;
+  int receiving_signal_count_ = 0;
+  int gathering_state_signal_count_ = 0;
+  int candidates_signal_count_ = 0;
+
+  // Used to make sure signals only come on signaling thread.
+  rtc::Thread* const signaling_thread_ = nullptr;
+  bool signaled_on_non_signaling_thread_ = false;
+};
+
+TEST_F(TransportControllerTest, TestSetIceReceivingTimeout) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+
+  transport_controller_->SetIceConnectionReceivingTimeout(1000);
+  EXPECT_EQ(1000, channel1->receiving_timeout());
+
+  // Test that value stored in controller is applied to new channels.
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  EXPECT_EQ(1000, channel2->receiving_timeout());
+}
+
+TEST_F(TransportControllerTest, TestSetSslMaxProtocolVersion) {
+  EXPECT_TRUE(transport_controller_->SetSslMaxProtocolVersion(
+      rtc::SSL_PROTOCOL_DTLS_12));
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+
+  ASSERT_NE(nullptr, channel);
+  EXPECT_EQ(rtc::SSL_PROTOCOL_DTLS_12, channel->ssl_max_protocol_version());
+
+  // Setting max version after transport is created should fail.
+  EXPECT_FALSE(transport_controller_->SetSslMaxProtocolVersion(
+      rtc::SSL_PROTOCOL_DTLS_10));
+}
+
+TEST_F(TransportControllerTest, TestSetIceRole) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLING, channel1->GetIceRole());
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLED);
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLED, channel1->GetIceRole());
+
+  // Test that value stored in controller is applied to new channels.
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLED, channel2->GetIceRole());
+}
+
+// Test that when one channel encounters a role conflict, the ICE role is
+// swapped on every channel.
+TEST_F(TransportControllerTest, TestIceRoleConflict) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLING, channel1->GetIceRole());
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLING, channel2->GetIceRole());
+
+  channel1->SignalRoleConflict(channel1);
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLED, channel1->GetIceRole());
+  EXPECT_EQ(cricket::ICEROLE_CONTROLLED, channel2->GetIceRole());
+}
+
+TEST_F(TransportControllerTest, TestGetSslRole) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+  ASSERT_TRUE(channel->SetSslRole(rtc::SSL_CLIENT));
+  rtc::SSLRole role;
+  EXPECT_TRUE(transport_controller_->GetSslRole(&role));
+  EXPECT_EQ(rtc::SSL_CLIENT, role);
+}
+
+TEST_F(TransportControllerTest, TestSetAndGetLocalCertificate) {
+  rtc::scoped_refptr<rtc::RTCCertificate> certificate1 =
+      rtc::RTCCertificate::Create(
+          rtc::scoped_ptr<rtc::SSLIdentity>(
+              rtc::SSLIdentity::Generate("session1", rtc::KT_DEFAULT))
+              .Pass());
+  rtc::scoped_refptr<rtc::RTCCertificate> certificate2 =
+      rtc::RTCCertificate::Create(
+          rtc::scoped_ptr<rtc::SSLIdentity>(
+              rtc::SSLIdentity::Generate("session2", rtc::KT_DEFAULT))
+              .Pass());
+  rtc::scoped_refptr<rtc::RTCCertificate> returned_certificate;
+
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+
+  EXPECT_TRUE(transport_controller_->SetLocalCertificate(certificate1));
+  EXPECT_TRUE(transport_controller_->GetLocalCertificate(
+      "audio", &returned_certificate));
+  EXPECT_EQ(certificate1->identity()->certificate().ToPEMString(),
+            returned_certificate->identity()->certificate().ToPEMString());
+
+  // Should fail if called for a nonexistant transport.
+  EXPECT_FALSE(transport_controller_->GetLocalCertificate(
+      "video", &returned_certificate));
+
+  // Test that identity stored in controller is applied to new channels.
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  EXPECT_TRUE(transport_controller_->GetLocalCertificate(
+      "video", &returned_certificate));
+  EXPECT_EQ(certificate1->identity()->certificate().ToPEMString(),
+            returned_certificate->identity()->certificate().ToPEMString());
+
+  // Shouldn't be able to change the identity once set.
+  EXPECT_FALSE(transport_controller_->SetLocalCertificate(certificate2));
+}
+
+TEST_F(TransportControllerTest, TestGetRemoteSSLCertificate) {
+  rtc::FakeSSLCertificate fake_certificate("fake_data");
+  rtc::scoped_ptr<rtc::SSLCertificate> returned_certificate;
+
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+
+  channel->SetRemoteSSLCertificate(&fake_certificate);
+  EXPECT_TRUE(transport_controller_->GetRemoteSSLCertificate(
+      "audio", returned_certificate.accept()));
+  EXPECT_EQ(fake_certificate.ToPEMString(),
+            returned_certificate->ToPEMString());
+
+  // Should fail if called for a nonexistant transport.
+  EXPECT_FALSE(transport_controller_->GetRemoteSSLCertificate(
+      "video", returned_certificate.accept()));
+}
+
+TEST_F(TransportControllerTest, TestSetLocalTransportDescription) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+  TransportDescription local_desc(
+      std::vector<std::string>(), kIceUfrag1, kIcePwd1, cricket::ICEMODE_FULL,
+      cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+  std::string err;
+  EXPECT_TRUE(transport_controller_->SetLocalTransportDescription(
+      "audio", local_desc, cricket::CA_OFFER, &err));
+  // Check that ICE ufrag and pwd were propagated to channel.
+  EXPECT_EQ(kIceUfrag1, channel->ice_ufrag());
+  EXPECT_EQ(kIcePwd1, channel->ice_pwd());
+  // We also expect that the channel started gathering as a result of the
+  // description being set.
+  EXPECT_EQ_WAIT(cricket::kIceGatheringGathering, gathering_state_, kTimeout);
+  EXPECT_EQ(1, gathering_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSetRemoteTransportDescription) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+  TransportDescription remote_desc(
+      std::vector<std::string>(), kIceUfrag1, kIcePwd1, cricket::ICEMODE_FULL,
+      cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+  std::string err;
+  EXPECT_TRUE(transport_controller_->SetRemoteTransportDescription(
+      "audio", remote_desc, cricket::CA_OFFER, &err));
+  // Check that ICE ufrag and pwd were propagated to channel.
+  EXPECT_EQ(kIceUfrag1, channel->remote_ice_ufrag());
+  EXPECT_EQ(kIcePwd1, channel->remote_ice_pwd());
+}
+
+TEST_F(TransportControllerTest, TestAddRemoteCandidates) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+  Candidates candidates;
+  candidates.push_back(CreateCandidate(1));
+  std::string err;
+  EXPECT_TRUE(
+      transport_controller_->AddRemoteCandidates("audio", candidates, &err));
+  EXPECT_EQ(1U, channel->remote_candidates().size());
+}
+
+TEST_F(TransportControllerTest, TestReadyForRemoteCandidates) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+  // We expect to be ready for remote candidates only after local and remote
+  // descriptions are set.
+  EXPECT_FALSE(transport_controller_->ReadyForRemoteCandidates("audio"));
+
+  std::string err;
+  TransportDescription remote_desc(
+      std::vector<std::string>(), kIceUfrag1, kIcePwd1, cricket::ICEMODE_FULL,
+      cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+  EXPECT_TRUE(transport_controller_->SetRemoteTransportDescription(
+      "audio", remote_desc, cricket::CA_OFFER, &err));
+  EXPECT_FALSE(transport_controller_->ReadyForRemoteCandidates("audio"));
+
+  TransportDescription local_desc(
+      std::vector<std::string>(), kIceUfrag2, kIcePwd2, cricket::ICEMODE_FULL,
+      cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+  EXPECT_TRUE(transport_controller_->SetLocalTransportDescription(
+      "audio", local_desc, cricket::CA_ANSWER, &err));
+  EXPECT_TRUE(transport_controller_->ReadyForRemoteCandidates("audio"));
+}
+
+TEST_F(TransportControllerTest, TestGetStats) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("audio", 2);
+  ASSERT_NE(nullptr, channel2);
+  FakeTransportChannel* channel3 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel3);
+
+  TransportStats stats;
+  EXPECT_TRUE(transport_controller_->GetStats("audio", &stats));
+  EXPECT_EQ("audio", stats.transport_name);
+  EXPECT_EQ(2U, stats.channel_stats.size());
+}
+
+// Test that transport gets destroyed when it has no more channels.
+TEST_F(TransportControllerTest, TestCreateAndDestroyChannel) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel2);
+  ASSERT_EQ(channel1, channel2);
+  FakeTransportChannel* channel3 = CreateChannel("audio", 2);
+  ASSERT_NE(nullptr, channel3);
+
+  // Using GetStats to check if transport is destroyed from an outside class's
+  // perspective.
+  TransportStats stats;
+  EXPECT_TRUE(transport_controller_->GetStats("audio", &stats));
+  DestroyChannel("audio", 2);
+  DestroyChannel("audio", 1);
+  EXPECT_TRUE(transport_controller_->GetStats("audio", &stats));
+  DestroyChannel("audio", 1);
+  EXPECT_FALSE(transport_controller_->GetStats("audio", &stats));
+}
+
+TEST_F(TransportControllerTest, TestSignalConnectionStateFailed) {
+  // Need controlling ICE role to get in failed state.
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+
+  // Should signal "failed" if any channel failed; channel is considered failed
+  // if it previously had a connection but now has none, and gathering is
+  // complete.
+  channel1->SetCandidatesGatheringComplete();
+  channel1->SetConnectionCount(1);
+  channel1->SetConnectionCount(0);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionFailed, connection_state_, kTimeout);
+  EXPECT_EQ(1, connection_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalConnectionStateConnected) {
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  FakeTransportChannel* channel3 = CreateChannel("video", 2);
+  ASSERT_NE(nullptr, channel3);
+
+  // First, have one channel connect, and another fail, to ensure that
+  // the first channel connecting didn't trigger a "connected" state signal.
+  // We should only get a signal when all are connected.
+  channel1->SetConnectionCount(2);
+  channel1->SetWritable(true);
+  channel3->SetCandidatesGatheringComplete();
+  channel3->SetConnectionCount(1);
+  channel3->SetConnectionCount(0);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionFailed, connection_state_, kTimeout);
+  // Signal count of 1 means that the only signal emitted was "failed".
+  EXPECT_EQ(1, connection_state_signal_count_);
+
+  // Destroy the failed channel to return to "connecting" state.
+  DestroyChannel("video", 2);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnecting, connection_state_,
+                 kTimeout);
+  EXPECT_EQ(2, connection_state_signal_count_);
+
+  // Make the remaining channel reach a connected state.
+  channel2->SetConnectionCount(2);
+  channel2->SetWritable(true);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnected, connection_state_, kTimeout);
+  EXPECT_EQ(3, connection_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalConnectionStateComplete) {
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  FakeTransportChannel* channel3 = CreateChannel("video", 2);
+  ASSERT_NE(nullptr, channel3);
+
+  // Similar to above test, but we're now reaching the completed state, which
+  // means only one connection per FakeTransportChannel.
+  channel1->SetCandidatesGatheringComplete();
+  channel1->SetConnectionCount(1);
+  channel1->SetWritable(true);
+  channel3->SetCandidatesGatheringComplete();
+  channel3->SetConnectionCount(1);
+  channel3->SetConnectionCount(0);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionFailed, connection_state_, kTimeout);
+  // Signal count of 1 means that the only signal emitted was "failed".
+  EXPECT_EQ(1, connection_state_signal_count_);
+
+  // Destroy the failed channel to return to "connecting" state.
+  DestroyChannel("video", 2);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnecting, connection_state_,
+                 kTimeout);
+  EXPECT_EQ(2, connection_state_signal_count_);
+
+  // Make the remaining channel reach a connected state.
+  channel2->SetCandidatesGatheringComplete();
+  channel2->SetConnectionCount(2);
+  channel2->SetWritable(true);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnected, connection_state_, kTimeout);
+  EXPECT_EQ(3, connection_state_signal_count_);
+
+  // Finally, transition to completed state.
+  channel2->SetConnectionCount(1);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionCompleted, connection_state_, kTimeout);
+  EXPECT_EQ(4, connection_state_signal_count_);
+}
+
+// Make sure that if we're "connected" and remove a transport, we stay in the
+// "connected" state.
+TEST_F(TransportControllerTest, TestDestroyTransportAndStayConnected) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+
+  channel1->SetCandidatesGatheringComplete();
+  channel1->SetConnectionCount(2);
+  channel1->SetWritable(true);
+  channel2->SetCandidatesGatheringComplete();
+  channel2->SetConnectionCount(2);
+  channel2->SetWritable(true);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnected, connection_state_, kTimeout);
+  EXPECT_EQ(1, connection_state_signal_count_);
+
+  // Destroy one channel, then "complete" the other one, so we reach
+  // a known state.
+  DestroyChannel("video", 1);
+  channel1->SetConnectionCount(1);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionCompleted, connection_state_, kTimeout);
+  // Signal count of 2 means the deletion didn't cause any unexpected signals
+  EXPECT_EQ(2, connection_state_signal_count_);
+}
+
+// If we destroy the last/only transport, we should simply transition to
+// "connecting".
+TEST_F(TransportControllerTest, TestDestroyLastTransportWhileConnected) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+
+  channel->SetCandidatesGatheringComplete();
+  channel->SetConnectionCount(2);
+  channel->SetWritable(true);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnected, connection_state_, kTimeout);
+  EXPECT_EQ(1, connection_state_signal_count_);
+
+  DestroyChannel("audio", 1);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionConnecting, connection_state_,
+                 kTimeout);
+  // Signal count of 2 means the deletion didn't cause any unexpected signals
+  EXPECT_EQ(2, connection_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalReceiving) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+
+  // Should signal receiving as soon as any channel is receiving.
+  channel1->SetReceiving(true);
+  EXPECT_TRUE_WAIT(receiving_, kTimeout);
+  EXPECT_EQ(1, receiving_signal_count_);
+
+  channel2->SetReceiving(true);
+  channel1->SetReceiving(false);
+  channel2->SetReceiving(false);
+  EXPECT_TRUE_WAIT(!receiving_, kTimeout);
+  EXPECT_EQ(2, receiving_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalGatheringStateGathering) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  // Connect starts candidate gathering.
+  channel1->Connect();
+  // Should be in the gathering state as soon as any transport starts gathering.
+  EXPECT_EQ_WAIT(cricket::kIceGatheringGathering, gathering_state_, kTimeout);
+  EXPECT_EQ(1, gathering_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalGatheringStateComplete) {
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+  FakeTransportChannel* channel3 = CreateChannel("data", 1);
+  ASSERT_NE(nullptr, channel3);
+
+  channel3->Connect();
+  EXPECT_EQ_WAIT(cricket::kIceGatheringGathering, gathering_state_, kTimeout);
+  EXPECT_EQ(1, gathering_state_signal_count_);
+
+  // Have one channel finish gathering, then destroy it, to make sure gathering
+  // completion wasn't signalled if only one transport finished gathering.
+  channel3->SetCandidatesGatheringComplete();
+  DestroyChannel("data", 1);
+  EXPECT_EQ_WAIT(cricket::kIceGatheringNew, gathering_state_, kTimeout);
+  EXPECT_EQ(2, gathering_state_signal_count_);
+
+  // Make remaining channels start and then finish gathering.
+  channel1->Connect();
+  channel2->Connect();
+  EXPECT_EQ_WAIT(cricket::kIceGatheringGathering, gathering_state_, kTimeout);
+  EXPECT_EQ(3, gathering_state_signal_count_);
+
+  channel1->SetCandidatesGatheringComplete();
+  channel2->SetCandidatesGatheringComplete();
+  EXPECT_EQ_WAIT(cricket::kIceGatheringComplete, gathering_state_, kTimeout);
+  EXPECT_EQ(4, gathering_state_signal_count_);
+}
+
+// Test that when the last transport that hasn't finished connecting and/or
+// gathering is destroyed, the aggregate state jumps to "completed". This can
+// happen if, for example, we have an audio and video transport, the audio
+// transport completes, then we start bundling video on the audio transport.
+TEST_F(TransportControllerTest,
+       TestSignalingWhenLastIncompleteTransportDestroyed) {
+  transport_controller_->SetIceRole(cricket::ICEROLE_CONTROLLING);
+  FakeTransportChannel* channel1 = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel1);
+  FakeTransportChannel* channel2 = CreateChannel("video", 1);
+  ASSERT_NE(nullptr, channel2);
+
+  channel1->SetCandidatesGatheringComplete();
+  EXPECT_EQ_WAIT(cricket::kIceGatheringGathering, gathering_state_, kTimeout);
+  EXPECT_EQ(1, gathering_state_signal_count_);
+
+  channel1->SetConnectionCount(1);
+  channel1->SetWritable(true);
+  DestroyChannel("video", 1);
+  EXPECT_EQ_WAIT(cricket::kIceConnectionCompleted, connection_state_, kTimeout);
+  EXPECT_EQ(1, connection_state_signal_count_);
+  EXPECT_EQ_WAIT(cricket::kIceGatheringComplete, gathering_state_, kTimeout);
+  EXPECT_EQ(2, gathering_state_signal_count_);
+}
+
+TEST_F(TransportControllerTest, TestSignalCandidatesGathered) {
+  FakeTransportChannel* channel = CreateChannel("audio", 1);
+  ASSERT_NE(nullptr, channel);
+
+  // Transport won't signal candidates until it has a local description.
+  TransportDescription local_desc(
+      std::vector<std::string>(), kIceUfrag1, kIcePwd1, cricket::ICEMODE_FULL,
+      cricket::CONNECTIONROLE_ACTPASS, nullptr, Candidates());
+  std::string err;
+  EXPECT_TRUE(transport_controller_->SetLocalTransportDescription(
+      "audio", local_desc, cricket::CA_OFFER, &err));
+
+  channel->SignalCandidateGathered(channel, CreateCandidate(1));
+  EXPECT_EQ_WAIT(1, candidates_signal_count_, kTimeout);
+  EXPECT_EQ(1U, candidates_["audio"].size());
+}
+
+TEST_F(TransportControllerTest, TestSignalingOccursOnSignalingThread) {
+  CreateTransportControllerWithWorkerThread();
+  CreateChannelsAndCompleteConnectionOnWorkerThread();
+
+  // connecting --> connected --> completed
+  EXPECT_EQ_WAIT(cricket::kIceConnectionCompleted, connection_state_, kTimeout);
+  EXPECT_EQ(2, connection_state_signal_count_);
+
+  EXPECT_TRUE_WAIT(receiving_, kTimeout);
+  EXPECT_EQ(1, receiving_signal_count_);
+
+  // new --> gathering --> complete
+  EXPECT_EQ_WAIT(cricket::kIceGatheringComplete, gathering_state_, kTimeout);
+  EXPECT_EQ(2, gathering_state_signal_count_);
+
+  EXPECT_EQ_WAIT(1U, candidates_["audio"].size(), kTimeout);
+  EXPECT_EQ_WAIT(1U, candidates_["video"].size(), kTimeout);
+  EXPECT_EQ(2, candidates_signal_count_);
+
+  EXPECT_TRUE(!signaled_on_non_signaling_thread_);
+}