base/test/statistics_delta_reader_unittest.cc

   1 // Copyright 2014 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/test/statistics_delta_reader.h"
   6
   7 #include "base/memory/scoped_ptr.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/metrics/histogram_samples.h"
  10 #include "testing/gtest/include/gtest/gtest.h"
  11
  12 namespace base {
  13
  14 TEST(StatisticsDeltaReaderTest, Scope) {
  15   // Record a histogram before the creation of the recorder.
  16   UMA_HISTOGRAM_BOOLEAN("Test", true);
  17
  18   StatisticsDeltaReader reader;
  19
  20   // Verify that no histogram is recorded.
  21   scoped_ptr<HistogramSamples> samples(
  22       reader.GetHistogramSamplesSinceCreation("Test"));
  23   EXPECT_FALSE(samples);
  24
  25   // Record a histogram after the creation of the recorder.
  26   UMA_HISTOGRAM_BOOLEAN("Test", true);
  27
  28   // Verify that one histogram is recorded.
  29   samples = reader.GetHistogramSamplesSinceCreation("Test");
  30   EXPECT_TRUE(samples);
  31   EXPECT_EQ(1, samples->TotalCount());
  32 }
  33
  34 }  // namespace base