Land Recent QUIC Changes

net/quic/congestion_control/rtt_stats_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/rtt_stats.h"
 
 #include "base/logging.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
@@ skipping 154 matching lines @@
 
   // Update once with a 20ms RTT.
   QuicTime::Delta doubled_rtt = initial_rtt.Multiply(2);
   rtt_stats_.UpdateRtt(doubled_rtt, QuicTime::Delta::Zero(), QuicTime::Zero());
   EXPECT_EQ(initial_rtt.Multiply(1.125), rtt_stats_.SmoothedRtt());
 
   // Expire the smoothed metrics, increasing smoothed rtt and mean deviation.
   rtt_stats_.ExpireSmoothedMetrics();
   EXPECT_EQ(doubled_rtt, rtt_stats_.SmoothedRtt());
   EXPECT_EQ(initial_rtt.Multiply(0.875), rtt_stats_.mean_deviation());
+
+  // Now go back down to 5ms and expire the smoothed metrics, and ensure the
+  // mean deviation increases to 15ms.
+  QuicTime::Delta half_rtt = initial_rtt.Multiply(0.5);
+  rtt_stats_.UpdateRtt(half_rtt, QuicTime::Delta::Zero(), QuicTime::Zero());
+  EXPECT_GT(doubled_rtt, rtt_stats_.SmoothedRtt());
+  EXPECT_LT(initial_rtt, rtt_stats_.mean_deviation());
 }
 
 }  // namespace test
 }  // namespace net