NQE: Add net log event if the metric changes substantially

net/nqe/network_quality_estimator_unittest.cc

 // Copyright 2015 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/nqe/network_quality_estimator.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <limits>
@@ skipping 208 matching lines @@
   // Both RTT and downstream throughput should be updated.
   base::TimeDelta http_rtt;
   EXPECT_TRUE(estimator.GetRecentHttpRTT(base::TimeTicks(), &http_rtt));
   EXPECT_TRUE(
       estimator.GetRecentDownlinkThroughputKbps(base::TimeTicks(), &kbps));
   base::TimeDelta transport_rtt;
   EXPECT_FALSE(
       estimator.GetRecentTransportRTT(base::TimeTicks(), &transport_rtt));
 
   // Verify the contents of the net log.
-  EXPECT_EQ(
+  EXPECT_LE(
       2, estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED));
   EXPECT_EQ(http_rtt.InMilliseconds(),
             estimator.GetNetLogLastIntegerValue(
                 NetLogEventType::NETWORK_QUALITY_CHANGED, "http_rtt_ms"));
   EXPECT_EQ(-1,
             estimator.GetNetLogLastIntegerValue(
                 NetLogEventType::NETWORK_QUALITY_CHANGED, "transport_rtt_ms"));
   EXPECT_EQ(kbps, estimator.GetNetLogLastIntegerValue(
                       NetLogEventType::NETWORK_QUALITY_CHANGED,
                       "downstream_throughput_kbps"));
@@ skipping 164 matching lines @@
   TestEffectiveConnectionTypeObserver observer;
   estimator.AddEffectiveConnectionTypeObserver(&observer);
   TestRTTObserver rtt_observer;
   estimator.AddRTTObserver(&rtt_observer);
   TestThroughputObserver throughput_observer;
   estimator.AddThroughputObserver(&throughput_observer);
 
   // |observer| should be notified as soon as it is added.
   base::RunLoop().RunUntilIdle();
   EXPECT_EQ(1U, observer.effective_connection_types().size());
-  EXPECT_EQ(
-      2, estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED));
+
+  int num_net_log_entries =
+      estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED);
+  EXPECT_LE(2, num_net_log_entries);
 
   estimator.SimulateNetworkChange(
       NetworkChangeNotifier::ConnectionType::CONNECTION_2G, "test");
   histogram_tester.ExpectBucketCount(
       "NQE.RTT.ObservationSource",
       NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE, 1);
   histogram_tester.ExpectBucketCount(
       "NQE.Kbps.ObservationSource",
       NETWORK_QUALITY_OBSERVATION_SOURCE_HTTP_CACHED_ESTIMATE, 1);
 
   // Verify the contents of the net log.
   EXPECT_LE(
-      3, estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED));
+      1, estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED) -
+             num_net_log_entries);
   EXPECT_NE(-1, estimator.GetNetLogLastIntegerValue(
                     NetLogEventType::NETWORK_QUALITY_CHANGED, "http_rtt_ms"));
   EXPECT_EQ(-1,
             estimator.GetNetLogLastIntegerValue(
                 NetLogEventType::NETWORK_QUALITY_CHANGED, "transport_rtt_ms"));
   EXPECT_NE(-1, estimator.GetNetLogLastIntegerValue(
                     NetLogEventType::NETWORK_QUALITY_CHANGED,
                     "downstream_throughput_kbps"));
   EXPECT_EQ(
       GetNameForEffectiveConnectionType(estimator.GetEffectiveConnectionType()),
@@ skipping 1295 matching lines @@
   estimator.set_start_time_null_downlink_throughput_kbps(100000);
 
   tick_clock_ptr->Advance(base::TimeDelta::FromMinutes(60));
 
   std::unique_ptr<URLRequest> request(context.CreateRequest(
       estimator.GetEchoURL(), DEFAULT_PRIORITY, &test_delegate));
   request->SetLoadFlags(request->load_flags() | LOAD_MAIN_FRAME_DEPRECATED);
   request->Start();
   base::RunLoop().Run();
   EXPECT_EQ(1U, observer.effective_connection_types().size());
-  EXPECT_EQ(
+  EXPECT_LE(
       1, estimator.GetEntriesCount(NetLogEventType::NETWORK_QUALITY_CHANGED));
 
   // Verify the contents of the net log.
   EXPECT_EQ(GetNameForEffectiveConnectionType(EFFECTIVE_CONNECTION_TYPE_2G),
             estimator.GetNetLogLastStringValue(
                 NetLogEventType::NETWORK_QUALITY_CHANGED,
                 "effective_connection_type"));
   EXPECT_EQ(1500, estimator.GetNetLogLastIntegerValue(
                       NetLogEventType::NETWORK_QUALITY_CHANGED, "http_rtt_ms"));
   EXPECT_EQ(-1,
@@ skipping 1359 matching lines @@
 
   // Cleanup.
   estimator.RemoveRTTObserver(&rtt_observer);
   estimator.RemoveThroughputObserver(&throughput_observer);
   estimator.RemoveRTTAndThroughputEstimatesObserver(&rtt_throughput_observer);
   estimator.RemoveEffectiveConnectionTypeObserver(
       &effective_connection_type_observer);
 }
 
 }  // namespace net