Fix exponential probing in ProbeController.

webrtc/modules/congestion_controller/probe_controller_unittest.cc

 /*
  *  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>
@@ skipping 54 matching lines @@
   probe_controller_->OnNetworkStateChanged(kNetworkUp);
 }
 
 TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncrease) {
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(AtLeast(2));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
   // Long enough to time out exponential probing.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probe_controller_->SetEstimatedBitrate(kStartBitrateBps);
+  probe_controller_->Process();
 
   EXPECT_CALL(pacer_, CreateProbeCluster(kMaxBitrateBps + 100, _));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps + 100);
 }
 
 TEST_F(ProbeControllerTest, TestExponentialProbing) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
 
+  // Repeated probe should only be sent when estimated bitrate climbs above 4 *
+  // kStartBitrateBps = 1200.
+  EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(0);
+  probe_controller_->SetEstimatedBitrate(1000);
+  testing::Mock::VerifyAndClearExpectations(&pacer_);
+
   EXPECT_CALL(pacer_, CreateProbeCluster(2 * 1800, _));
   probe_controller_->SetEstimatedBitrate(1800);
 }
 
 TEST_F(ProbeControllerTest, TestExponentialProbingTimeout) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
 
   // Advance far enough to cause a time out in waiting for probing result.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
-  EXPECT_CALL(pacer_, CreateProbeCluster(2 * 1800, _)).Times(0);
+  probe_controller_->Process();
+
+  EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(0);
   probe_controller_->SetEstimatedBitrate(1800);
 }
 
 TEST_F(ProbeControllerTest, ProbeAfterEstimateDropInAlr) {
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(2);
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
   probe_controller_->SetEstimatedBitrate(500);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 
   // When bandwidth estimate drops the controller should send a probe at the
   // previous bitrate.
   EXPECT_CALL(pacer_, CreateProbeCluster(500, _)).Times(1);
   EXPECT_CALL(pacer_, GetApplicationLimitedRegionStartTime())
       .WillRepeatedly(
           Return(rtc::Optional<int64_t>(clock_.TimeInMilliseconds())));
   clock_.AdvanceTimeMilliseconds(kAlrProbeInterval + 1);
+  probe_controller_->Process();
   probe_controller_->SetEstimatedBitrate(50);
 }
 
 TEST_F(ProbeControllerTest, PeriodicProbing) {
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(2);
   probe_controller_->EnablePeriodicAlrProbing(true);
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
   probe_controller_->SetEstimatedBitrate(500);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
@@ skipping 22 matching lines @@
   EXPECT_CALL(pacer_, GetApplicationLimitedRegionStartTime())
       .WillRepeatedly(Return(rtc::Optional<int64_t>(start_time)));
   clock_.AdvanceTimeMilliseconds(1000);
   probe_controller_->Process();
   probe_controller_->SetEstimatedBitrate(500);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 }
 
 }  // namespace test
 }  // namespace webrtc