net/quic/congestion_control/hybrid_slow_start_test.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/quic/congestion_control/hybrid_slow_start.h"
   6
   7 #include "base/logging.h"
   8 #include "base/memory/scoped_ptr.h"
   9 #include "testing/gtest/include/gtest/gtest.h"
  10
  11 namespace net {
  12 namespace test {
  13
  14 class HybridSlowStartTest : public ::testing::Test {
  15  protected:
  16   HybridSlowStartTest()
  17      : one_ms_(QuicTime::Delta::FromMilliseconds(1)),
  18        rtt_(QuicTime::Delta::FromMilliseconds(60)) {
  19   }
  20   void SetUp() override { slow_start_.reset(new HybridSlowStart()); }
  21   const QuicTime::Delta one_ms_;
  22   const QuicTime::Delta rtt_;
  23   scoped_ptr<HybridSlowStart> slow_start_;
  24 };
  25
  26 TEST_F(HybridSlowStartTest, Simple) {
  27   QuicPacketNumber packet_number = 1;
  28   QuicPacketNumber end_packet_number = 3;
  29   slow_start_->StartReceiveRound(end_packet_number);
  30
  31   EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
  32
  33   // Test duplicates.
  34   EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number));
  35
  36   EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
  37   EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
  38
  39   // Test without a new registered end_packet_number;
  40   EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
  41
  42   end_packet_number = 20;
  43   slow_start_->StartReceiveRound(end_packet_number);
  44   while (packet_number < end_packet_number) {
  45     EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
  46   }
  47   EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
  48 }
  49
  50 TEST_F(HybridSlowStartTest, Delay) {
  51   // We expect to detect the increase at +1/8 of the RTT; hence at a typical
  52   // RTT of 60ms the detection will happen at 67.5 ms.
  53   const int kHybridStartMinSamples = 8;  // Number of acks required to trigger.
  54
  55   QuicPacketNumber end_packet_number = 1;
  56   slow_start_->StartReceiveRound(end_packet_number++);
  57
  58   // Will not trigger since our lowest RTT in our burst is the same as the long
  59   // term RTT provided.
  60   for (int n = 0; n < kHybridStartMinSamples; ++n) {
  61     EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
  62         rtt_.Add(QuicTime::Delta::FromMilliseconds(n)), rtt_, 100));
  63   }
  64   slow_start_->StartReceiveRound(end_packet_number++);
  65   for (int n = 1; n < kHybridStartMinSamples; ++n) {
  66     EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
  67         rtt_.Add(QuicTime::Delta::FromMilliseconds(n + 10)), rtt_, 100));
  68   }
  69   // Expect to trigger since all packets in this burst was above the long term
  70   // RTT provided.
  71   EXPECT_TRUE(slow_start_->ShouldExitSlowStart(
  72       rtt_.Add(QuicTime::Delta::FromMilliseconds(10)), rtt_, 100));
  73 }
  74
  75 }  // namespace test
  76 }  // namespace net