Reland of "Change TWCC send interval to reduce overhead on low BW situations."

webrtc/modules/remote_bitrate_estimator/remote_estimator_proxy_unittest.cc

 /*
  *  Copyright (c) 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.
  */
 
@@ skipping 24 matching lines @@
   void IncomingPacket(uint16_t seq, int64_t time_ms) {
     RTPHeader header;
     header.extension.hasTransportSequenceNumber = true;
     header.extension.transportSequenceNumber = seq;
     header.ssrc = kMediaSsrc;
     proxy_.IncomingPacket(time_ms, kDefaultPacketSize, header);
   }
 
   void Process() {
     clock_.AdvanceTimeMilliseconds(
-        RemoteEstimatorProxy::kDefaultProcessIntervalMs);
+        RemoteEstimatorProxy::kDefaultSendIntervalMs);
     proxy_.Process();
   }
 
   SimulatedClock clock_;
   testing::StrictMock<MockPacketRouter> router_;
   RemoteEstimatorProxy proxy_;
 
   const size_t kDefaultPacketSize = 100;
   const uint32_t kMediaSsrc = 456;
   const uint16_t kBaseSeq = 10;
@@ skipping 287 matching lines @@
         EXPECT_EQ(kBaseTimeMs - 1,
                   (packet->GetBaseTimeUs() + delta_vec[0]) / 1000);
         EXPECT_EQ(kTimeoutTimeMs - kBaseTimeMs, delta_vec[1] / 1000);
         EXPECT_EQ(1, delta_vec[2] / 1000);
         return true;
       }));
 
   Process();
 }
 
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsZeroBeforeFirstProcess) {
+  EXPECT_EQ(0, proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsDefaultOnUnkownBitrate) {
+  Process();
+  EXPECT_EQ(RemoteEstimatorProxy::kDefaultSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsMinIntervalOn300kbps) {
+  Process();
+  proxy_.OnBitrateChanged(300000);
+  EXPECT_EQ(RemoteEstimatorProxy::kMinSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsMaxIntervalOn0kbps) {
+  Process();
+  // TimeUntilNextProcess should be limited by |kMaxSendIntervalMs| when
+  // bitrate is small. We choose 0 bps as a special case, which also tests
+  // erroneous behaviors like division-by-zero.
+  proxy_.OnBitrateChanged(0);
+  EXPECT_EQ(RemoteEstimatorProxy::kMaxSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TimeUntilNextProcessIsMaxIntervalOn20kbps) {
+  Process();
+  proxy_.OnBitrateChanged(20000);
+  EXPECT_EQ(RemoteEstimatorProxy::kMaxSendIntervalMs,
+            proxy_.TimeUntilNextProcess());
+}
+
+TEST_F(RemoteEstimatorProxyTest, TwccReportsUse5PercentOfAvailableBandwidth) {
+  Process();
+  proxy_.OnBitrateChanged(80000);
+  // 80kbps * 0.05 = TwccReportSize(68B * 8b/B) * 1000ms / SendInterval(136ms)
+  EXPECT_EQ(136, proxy_.TimeUntilNextProcess());
+}
+
 }  // namespace webrtc