chrome/test/base/uma_histogram_helper.cc

   1 // Copyright (c) 2012 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 "chrome/test/base/uma_histogram_helper.h"
   6
   7 #include "base/bind.h"
   8 #include "base/metrics/statistics_recorder.h"
   9 #include "base/test/test_timeouts.h"
  10 #include "chrome/test/base/ui_test_utils.h"
  11 #include "content/public/browser/histogram_fetcher.h"
  12
  13 UMAHistogramHelper::UMAHistogramHelper() {
  14 }
  15
  16 void UMAHistogramHelper::Fetch() {
  17   base::Closure callback = base::Bind(&UMAHistogramHelper::FetchCallback,
  18                                       base::Unretained(this));
  19
  20   content::FetchHistogramsAsynchronously(
  21       base::MessageLoop::current(),
  22       callback,
  23       // If this call times out, it means that a child process is not
  24       // responding, which is something we should not ignore.  The timeout is
  25       // set to be longer than the normal browser test timeout so that it will
  26       // be prempted by the normal timeout.
  27       TestTimeouts::action_max_timeout() * 2);
  28   content::RunMessageLoop();
  29 }
  30
  31 void UMAHistogramHelper::ExpectUniqueSample(
  32     const std::string& name,
  33     base::HistogramBase::Sample sample,
  34     base::HistogramBase::Count expected_count) {
  35   base::HistogramBase* histogram =
  36       base::StatisticsRecorder::FindHistogram(name);
  37   EXPECT_NE(static_cast<base::HistogramBase*>(NULL), histogram)
  38       << "Histogram \"" << name << "\" does not exist.";
  39
  40   if (histogram) {
  41     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
  42     CheckBucketCount(name, sample, expected_count, *samples);
  43     CheckTotalCount(name, expected_count, *samples);
  44   }
  45 }
  46
  47 void UMAHistogramHelper::ExpectBucketCount(
  48     const std::string& name,
  49     base::HistogramBase::Sample sample,
  50     base::HistogramBase::Count expected_count) {
  51   base::HistogramBase* histogram =
  52       base::StatisticsRecorder::FindHistogram(name);
  53   EXPECT_NE(static_cast<base::HistogramBase*>(NULL), histogram)
  54       << "Histogram \"" << name << "\" does not exist.";
  55
  56   if (histogram) {
  57     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
  58     CheckBucketCount(name, sample, expected_count, *samples);
  59   }
  60 }
  61
  62 void UMAHistogramHelper::ExpectTotalCount(
  63     const std::string& name,
  64     base::HistogramBase::Count count) {
  65   base::HistogramBase* histogram =
  66       base::StatisticsRecorder::FindHistogram(name);
  67   if (histogram) {
  68     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
  69     CheckTotalCount(name, count, *samples);
  70   } else {
  71     // No histogram means there were zero samples.
  72     EXPECT_EQ(count, 0) << "Histogram \"" << name << "\" does not exist.";
  73   }
  74 }
  75
  76 void UMAHistogramHelper::FetchCallback() {
  77   base::MessageLoopForUI::current()->Quit();
  78 }
  79
  80 void UMAHistogramHelper::CheckBucketCount(
  81     const std::string& name,
  82     base::HistogramBase::Sample sample,
  83     base::HistogramBase::Count expected_count,
  84     base::HistogramSamples& samples) {
  85   EXPECT_EQ(expected_count, samples.GetCount(sample))
  86       << "Histogram \"" << name
  87       << "\" does not have the right number of samples (" << expected_count
  88       << ") in the expected bucket (" << sample << ").";
  89 }
  90
  91 void UMAHistogramHelper::CheckTotalCount(
  92     const std::string& name,
  93     base::HistogramBase::Count expected_count,
  94     base::HistogramSamples& samples) {
  95   EXPECT_EQ(expected_count, samples.TotalCount())
  96       << "Histogram \"" << name
  97       << "\" does not have the right total number of samples ("
  98       << expected_count << ").";
  99 }