Avoid cluster set up at max bitrate at start

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 11 matching lines @@
 
 namespace webrtc {
 namespace test {
 
 namespace {
 
 constexpr int kMinBitrateBps = 100;
 constexpr int kStartBitrateBps = 300;
 constexpr int kMaxBitrateBps = 1000;
 
+constexpr int kExponentialProbingTimeoutMs = 5000;
+
 }  // namespace
 
 class ProbeControllerTest : public ::testing::Test {
  protected:
   ProbeControllerTest() : clock_(0) {
     probe_controller_.reset(new ProbeController(&pacer_, &clock_));
   }
   ~ProbeControllerTest() override {}
 
   SimulatedClock clock_;
   NiceMock<MockPacedSender> pacer_;
   std::unique_ptr<ProbeController> probe_controller_;
 };
 
 TEST_F(ProbeControllerTest, InitiatesProbingAtStart) {
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(AtLeast(2));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
 }
 
 TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncrease) {
   EXPECT_CALL(pacer_, CreateProbeCluster(_, _)).Times(AtLeast(2));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
-  clock_.AdvanceTimeMilliseconds(25);
+  // Long enough to time out exponential probing.
+  clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
+  probe_controller_->SetEstimatedBitrate(kStartBitrateBps);
 
-  probe_controller_->SetEstimatedBitrate(kStartBitrateBps);
   EXPECT_CALL(pacer_, CreateProbeCluster(kMaxBitrateBps + 100, _));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps + 100);
 }
 
 TEST_F(ProbeControllerTest, TestExponentialProbing) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
   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(5000);
+  clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   EXPECT_CALL(pacer_, CreateProbeCluster(2 * 1800, _)).Times(0);
   probe_controller_->SetEstimatedBitrate(1800);
 }
 
 }  // namespace test
 }  // namespace webrtc