base/metrics/histogram_delta_serialization_unittest.cc

   1 // Copyright 2013 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 "base/metrics/histogram_delta_serialization.h"
   6
   7 #include <vector>
   8
   9 #include "base/metrics/histogram.h"
  10 #include "base/metrics/histogram_base.h"
  11 #include "base/metrics/statistics_recorder.h"
  12 #include "testing/gtest/include/gtest/gtest.h"
  13
  14 namespace base {
  15
  16 TEST(HistogramDeltaSerializationTest, DeserializeHistogramAndAddSamples) {
  17   StatisticsRecorder statistic_recorder;
  18   HistogramDeltaSerialization serializer("HistogramDeltaSerializationTest");
  19   std::vector<std::string> deltas;
  20   // Nothing was changed yet.
  21   serializer.PrepareAndSerializeDeltas(&deltas);
  22   EXPECT_TRUE(deltas.empty());
  23
  24   HistogramBase* histogram = Histogram::FactoryGet(
  25       "TestHistogram", 1, 1000, 10, HistogramBase::kIPCSerializationSourceFlag);
  26   histogram->Add(1);
  27   histogram->Add(10);
  28   histogram->Add(100);
  29   histogram->Add(1000);
  30
  31   serializer.PrepareAndSerializeDeltas(&deltas);
  32   EXPECT_FALSE(deltas.empty());
  33
  34   HistogramDeltaSerialization::DeserializeAndAddSamples(deltas);
  35
  36   // The histogram has kIPCSerializationSourceFlag. So samples will be ignored.
  37   scoped_ptr<HistogramSamples> snapshot(histogram->SnapshotSamples());
  38   EXPECT_EQ(1, snapshot->GetCount(1));
  39   EXPECT_EQ(1, snapshot->GetCount(10));
  40   EXPECT_EQ(1, snapshot->GetCount(100));
  41   EXPECT_EQ(1, snapshot->GetCount(1000));
  42
  43   // Clear kIPCSerializationSourceFlag to emulate multi-process usage.
  44   histogram->ClearFlags(HistogramBase::kIPCSerializationSourceFlag);
  45   HistogramDeltaSerialization::DeserializeAndAddSamples(deltas);
  46
  47   scoped_ptr<HistogramSamples> snapshot2(histogram->SnapshotSamples());
  48   EXPECT_EQ(2, snapshot2->GetCount(1));
  49   EXPECT_EQ(2, snapshot2->GetCount(10));
  50   EXPECT_EQ(2, snapshot2->GetCount(100));
  51   EXPECT_EQ(2, snapshot2->GetCount(1000));
  52 }
  53
  54 }  // namespace base