Serialize/Deserialize support in HistogramBase

base/metrics/histogram_base_unittest.cc

Index: base/metrics/histogram_base_unittest.cc
diff --git a/base/metrics/histogram_base_unittest.cc b/base/metrics/histogram_base_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4944f31790ba35dda3cbebeded439635027a6858
--- /dev/null
+++ b/base/metrics/histogram_base_unittest.cc
@@ -0,0 +1,172 @@
+// Copyright (c) 2012 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 <vector>
+
+#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_base.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/metrics/statistics_recorder.h"
+#include "base/pickle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+class HistogramBaseTest : public testing::Test {
+ protected:
+  HistogramBaseTest() {
+    // Each test will have a clean state (no Histogram / BucketRanges
+    // registered).
+    statistics_recorder_ = NULL;
+    ResetStatisticsRecorder();
+  }
+
+  virtual ~HistogramBaseTest() {
+    delete statistics_recorder_;
+  }
+
+  void ResetStatisticsRecorder() {
+    delete statistics_recorder_;
+    statistics_recorder_ = new StatisticsRecorder();
+  }
+
+ private:
+  StatisticsRecorder* statistics_recorder_;
+};
+
+TEST_F(HistogramBaseTest, DeserializeHistogram) {
+  HistogramBase* histogram = Histogram::FactoryGet(
+      "TestHistogram", 1, 1000, 10,
+      (HistogramBase::kUmaTargetedHistogramFlag |
+      HistogramBase::kIPCSerializationSourceFlag));
+
+  Pickle pickle;
+  ASSERT_TRUE(histogram->SerializeInfo(&pickle));
+
+  PickleIterator iter(pickle);
+  HistogramBase* deserialized = DeserializeHistogramInfo(&iter);
+  EXPECT_EQ(histogram, deserialized);
+
+  ResetStatisticsRecorder();
+
+  PickleIterator iter2(pickle);
+  deserialized = DeserializeHistogramInfo(&iter2);
+  EXPECT_TRUE(deserialized);
+  EXPECT_NE(histogram, deserialized);
+  EXPECT_EQ("TestHistogram", deserialized->histogram_name());
+  EXPECT_TRUE(deserialized->HasConstructionArguments(1, 1000, 10));
+
+  // kIPCSerializationSourceFlag will be cleared.
+  EXPECT_EQ(HistogramBase::kUmaTargetedHistogramFlag, deserialized->flags());
+}
+
+TEST_F(HistogramBaseTest, DeserializeHistogramAndAddSamples) {
+  HistogramBase* histogram = Histogram::FactoryGet(
+      "TestHistogram", 1, 1000, 10, HistogramBase::kIPCSerializationSourceFlag);
+  histogram->Add(1);
+  histogram->Add(10);
+  histogram->Add(100);
+  histogram->Add(1000);
+
+  Pickle pickle;
+  ASSERT_TRUE(histogram->SerializeInfo(&pickle));
+  histogram->SnapshotSamples()->Serialize(&pickle);
+
+  PickleIterator iter(pickle);
+  DeserializeHistogramAndAddSamples(&iter);
+
+  // The histogram has kIPCSerializationSourceFlag. So samples will be ignored.
+  scoped_ptr<HistogramSamples> snapshot(histogram->SnapshotSamples());
+  EXPECT_EQ(1, snapshot->GetCount(1));
+  EXPECT_EQ(1, snapshot->GetCount(10));
+  EXPECT_EQ(1, snapshot->GetCount(100));
+  EXPECT_EQ(1, snapshot->GetCount(1000));
+
+  // Clear kIPCSerializationSourceFlag to emulate multi-process usage.
+  histogram->ClearFlags(HistogramBase::kIPCSerializationSourceFlag);
+  PickleIterator iter2(pickle);
+  DeserializeHistogramAndAddSamples(&iter2);
+
+  scoped_ptr<HistogramSamples> snapshot2(histogram->SnapshotSamples());
+  EXPECT_EQ(2, snapshot2->GetCount(1));
+  EXPECT_EQ(2, snapshot2->GetCount(10));
+  EXPECT_EQ(2, snapshot2->GetCount(100));
+  EXPECT_EQ(2, snapshot2->GetCount(1000));
+}
+
+TEST_F(HistogramBaseTest, DeserializeLinearHistogram) {
+  HistogramBase* histogram = LinearHistogram::FactoryGet(
+      "TestHistogram", 1, 1000, 10,
+      HistogramBase::kIPCSerializationSourceFlag);
+
+  Pickle pickle;
+  ASSERT_TRUE(histogram->SerializeInfo(&pickle));
+
+  PickleIterator iter(pickle);
+  HistogramBase* deserialized = DeserializeHistogramInfo(&iter);
+  EXPECT_EQ(histogram, deserialized);
+
+  ResetStatisticsRecorder();
+
+  PickleIterator iter2(pickle);
+  deserialized = DeserializeHistogramInfo(&iter2);
+  EXPECT_TRUE(deserialized);
+  EXPECT_NE(histogram, deserialized);
+  EXPECT_EQ("TestHistogram", deserialized->histogram_name());
+  EXPECT_TRUE(deserialized->HasConstructionArguments(1, 1000, 10));
+  EXPECT_EQ(0, deserialized->flags());
+}
+
+TEST_F(HistogramBaseTest, DeserializeBooleanHistogram) {
+  HistogramBase* histogram = BooleanHistogram::FactoryGet(
+      "TestHistogram", HistogramBase::kIPCSerializationSourceFlag);
+
+  Pickle pickle;
+  ASSERT_TRUE(histogram->SerializeInfo(&pickle));
+
+  PickleIterator iter(pickle);
+  HistogramBase* deserialized = DeserializeHistogramInfo(&iter);
+  EXPECT_EQ(histogram, deserialized);
+
+  ResetStatisticsRecorder();
+
+  PickleIterator iter2(pickle);
+  deserialized = DeserializeHistogramInfo(&iter2);
+  EXPECT_TRUE(deserialized);
+  EXPECT_NE(histogram, deserialized);
+  EXPECT_EQ("TestHistogram", deserialized->histogram_name());
+  EXPECT_TRUE(deserialized->HasConstructionArguments(1, 2, 3));
+  EXPECT_EQ(0, deserialized->flags());
+}
+
+TEST_F(HistogramBaseTest, DeserializeCustomHistogram) {
+  std::vector<HistogramBase::Sample> ranges;
+  ranges.push_back(13);
+  ranges.push_back(5);
+  ranges.push_back(9);
+
+  HistogramBase* histogram = CustomHistogram::FactoryGet(
+      "TestHistogram", ranges, HistogramBase::kIPCSerializationSourceFlag);
+
+  Pickle pickle;
+  ASSERT_TRUE(histogram->SerializeInfo(&pickle));
+
+  PickleIterator iter(pickle);
+  HistogramBase* deserialized = DeserializeHistogramInfo(&iter);
+  EXPECT_EQ(histogram, deserialized);
+
+  ResetStatisticsRecorder();
+
+  PickleIterator iter2(pickle);
+  deserialized = DeserializeHistogramInfo(&iter2);
+  EXPECT_TRUE(deserialized);
+  EXPECT_NE(histogram, deserialized);
+  EXPECT_EQ("TestHistogram", deserialized->histogram_name());
+  EXPECT_TRUE(deserialized->HasConstructionArguments(5, 13, 4));
+  EXPECT_EQ(0, deserialized->flags());
+}
+
+// TODO(kaiwang): Add SparseHistogram test.
+
+}  // namespace base