Adding ChannelController to audio network adaptor.

webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc

Index: webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc
diff --git a/webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc b/webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..58a074ceade7db8f64265be17aee053fc66d0cc0
--- /dev/null
+++ b/webrtc/modules/audio_coding/audio_network_adaptor/channel_controller_unittest.cc
@@ -0,0 +1,76 @@
+/*
+ *  Copyright (c) 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 <memory>
+
+#include "webrtc/modules/audio_coding/audio_network_adaptor/channel_controller.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace webrtc {
+
+namespace {
+constexpr size_t kNumChannels = 2;
+constexpr int kChannel1To2BandwidthBps = 31000;
+constexpr int kChannel2To1BandwidthBps = 29000;
+}  // namespace
+
+class ChannelControllerTest : public ::testing::Test {

[hlundin-webrtc, 2016/09/08 07:47:44]

I think you should avoid having a test fixture. The tests are simple enough
without them. You can still use some convenience functions (in an unnamed
namespace). For instance:

std::unique_ptr<ChannelController> CreateChannelController();
void SetUplinkBandwidth(int uplink_bandwidth_bps, Controller::NetworkMetrics*
metrics);

[minyue-webrtc, 2016/09/08 08:37:00]

Ok. I removed the fixture.

+ protected:
+  ChannelControllerTest()
+      : channel_controller_(new ChannelController(
+            ChannelController::Config(kNumChannels,
+                                      kNumChannels,
+                                      kChannel1To2BandwidthBps,
+                                      kChannel2To1BandwidthBps))) {}
+
+  void SetUplinkBandwidth(int uplink_bandwidth_bps) {
+    metrics_.uplink_bandwidth_bps = rtc::Optional<int>(uplink_bandwidth_bps);
+  }
+
+  void CheckChannelDecision(size_t channel) const {
+    AudioNetworkAdaptor::EncoderRuntimeConfig config;
+    channel_controller_->MakeDecision(metrics_, &config);
+    ASSERT_TRUE(config.num_channels);

[hlundin-webrtc, 2016/09/08 07:47:44]

You can replace these two lines with one:
EXPECT_EQ(rtc::Optional<size_t>(channel), config.num_channels);

[minyue-webrtc, 2016/09/08 08:37:00]

Done.

+    EXPECT_EQ(channel, *config.num_channels);
+  }
+
+  std::unique_ptr<ChannelController> channel_controller_;
+  Controller::NetworkMetrics metrics_;
+};
+
+TEST_F(ChannelControllerTest, OutputInitValueWhenUplinkBandwidthUnknown) {
+  CheckChannelDecision(kNumChannels);
+}
+
+TEST_F(ChannelControllerTest, OutputCorrectValuesWhenUplinkBandwidthChanges) {
+  // Use low bandwidth to ensure output is 1.
+  SetUplinkBandwidth(kChannel2To1BandwidthBps);
+  CheckChannelDecision(1);
+
+  constexpr int kBandwidth =
+      (kChannel1To2BandwidthBps + kChannel2To1BandwidthBps) / 2;
+  // Use between-thresholds bandwidth to check output remains at 1.
+  SetUplinkBandwidth(kBandwidth);
+  CheckChannelDecision(1);
+
+  // Use high bandwidth to check output switch to 2.
+  SetUplinkBandwidth(kChannel1To2BandwidthBps);
+  CheckChannelDecision(2);
+
+  // Use between-thresholds bandwidth to check output remains at 2.
+  SetUplinkBandwidth(kBandwidth);
+  CheckChannelDecision(2);
+
+  // Use low bandwidth to check output switch to 1.
+  SetUplinkBandwidth(kChannel2To1BandwidthBps);
+  CheckChannelDecision(1);

[hlundin-webrtc, 2016/09/08 07:47:45]

Add tests to verify that it switches immediately from 1 to 2 and back when the
uplink bw changes across the hysteresis zone without first landing in the
dead-zone.

[minyue-webrtc, 2016/09/08 08:37:00]

Done.

+}
+
+}  // namespace webrtc