Test only change to QUIC TCPLossAlgorithmTest to ensure the early

net/quic/congestion_control/tcp_loss_algorithm_test.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/congestion_control/tcp_loss_algorithm.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/stl_util.h"
@@ skipping 111 matching lines @@
   clock_.AdvanceTime(srtt_.Multiply(1.25));
   QuicPacketSequenceNumber lost[] = { 1 };
   VerifyLosses(2, lost, arraysize(lost));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(TcpLossAlgorithmTest, EarlyRetransmitAllPackets) {
   const size_t kNumSentPackets = 5;
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
+    // Advance the time 1/4 RTT between 3 and 4.
+    if (i == 3) {
+      clock_.AdvanceTime(srtt_.Multiply(0.25));
+    }
   }
-  // Early retransmit when the final packet gets acked and the first 4 are
-  // nacked multiple times via FACK.
+
+  // Early retransmit when the final packet gets acked and 1.25 RTTs have
+  // elapsed since the packets were sent.
   unacked_packets_.SetNotPending(kNumSentPackets);
+  // This simulates a single ack following multiple missing packets with FACK.
   for (size_t i = 1; i < kNumSentPackets; ++i) {
     unacked_packets_.NackPacket(i, kNumSentPackets - i);
   }
   QuicPacketSequenceNumber lost[] = { 1, 2 };
   VerifyLosses(kNumSentPackets, lost, arraysize(lost));
-  EXPECT_EQ(clock_.Now().Add(srtt_.Multiply(1.25)),
+  // The time has already advanced 1/4 an RTT, so ensure the timeout is set
+  // 1.25 RTTs after the earliest pending packet(3), not the last(4).
+  EXPECT_EQ(clock_.Now().Add(srtt_),
             loss_algorithm_.GetLossTimeout());
 
-  clock_.AdvanceTime(srtt_.Multiply(1.25));
-  QuicPacketSequenceNumber lost2[] = { 1, 2, 3, 4 };
+  clock_.AdvanceTime(srtt_);
+  QuicPacketSequenceNumber lost2[] = { 1, 2, 3 };
   VerifyLosses(kNumSentPackets, lost2, arraysize(lost2));
+  EXPECT_EQ(clock_.Now().Add(srtt_.Multiply(0.25)),
+            loss_algorithm_.GetLossTimeout());
+  clock_.AdvanceTime(srtt_.Multiply(0.25));
+  QuicPacketSequenceNumber lost3[] = { 1, 2, 3, 4 };
+  VerifyLosses(kNumSentPackets, lost3, arraysize(lost3));
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 TEST_F(TcpLossAlgorithmTest, DontEarlyRetransmitNeuteredPacket) {
   const size_t kNumSentPackets = 2;
   // Transmit 2 packets.
   for (size_t i = 1; i <= kNumSentPackets; ++i) {
     SendDataPacket(i);
   }
   // Early retransmit when the final packet gets acked and the first is nacked.
   unacked_packets_.SetNotPending(2);
   unacked_packets_.NackPacket(1, 1);
   unacked_packets_.NeuterPacket(1);
   VerifyLosses(2, NULL, 0);
   EXPECT_EQ(QuicTime::Zero(), loss_algorithm_.GetLossTimeout());
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net