Add HistogramTester::GetAllSamples.

base/test/histogram_tester.cc

 // Copyright 2014 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 "base/test/histogram_tester.h"
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_samples.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/stl_util.h"
@@ skipping 55 matching lines @@
       base::StatisticsRecorder::FindHistogram(name);
   if (histogram) {
     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
     CheckTotalCount(name, count, *samples);
   } else {
     // No histogram means there were zero samples.
     EXPECT_EQ(count, 0) << "Histogram \"" << name << "\" does not exist.";
   }
 }
 
+std::vector<Bucket> HistogramTester::GetAllSamples(const std::string& name) {
+  std::vector<Bucket> samples;
+  scoped_ptr<HistogramSamples> snapshot =
+      GetHistogramSamplesSinceCreation(name);
+  for (auto it = snapshot->Iterator(); !it->Done(); it->Next()) {
+    HistogramBase::Sample sample;
+    HistogramBase::Count count;
+    it->Get(&sample, nullptr, &count);
+    samples.push_back(Bucket(sample, count));
+  }
+  return samples;
+}
+
 scoped_ptr<HistogramSamples> HistogramTester::GetHistogramSamplesSinceCreation(
     const std::string& histogram_name) {
   HistogramBase* histogram = StatisticsRecorder::FindHistogram(histogram_name);
   if (!histogram)
     return scoped_ptr<HistogramSamples>();
   scoped_ptr<HistogramSamples> named_samples(histogram->SnapshotSamples());
   HistogramSamples* named_original_samples =
       histograms_snapshot_[histogram_name];
   if (named_original_samples)
     named_samples->Subtract(*named_original_samples);
@@ skipping 27 matching lines @@
   histogram_data = histograms_snapshot_.find(name);
   if (histogram_data != histograms_snapshot_.end())
     actual_count -= histogram_data->second->TotalCount();
 
   EXPECT_EQ(expected_count, actual_count)
       << "Histogram \"" << name
       << "\" does not have the right total number of samples ("
       << expected_count << "). It has (" << actual_count << ").";
 }
 
+bool Bucket::operator==(const Bucket& other) const {
+  return min_ == other.min_ && count_ == other.count_;
+}
+
+void PrintTo(const Bucket& bucket, std::ostream* os) {
+  *os << bucket.count_ << (bucket.count_ == 1 ? " sample " : " samples ")
+      << "in bucket " << bucket.min_;

[Ilya Sherman, 2015/06/27 07:25:19]

WDYT of something shorter, like the following?

  *os << bucket.min << ": " << bucket.count;  // e.g. "1: 4"

I'm not really sure -- that might be too dense, and not much clearer than a
pair.  I guess I'm trying to find something a little denser, without being so
dense as to be confusing.

[twifkak, 2015/06/29 21:52:29]

That doesn't seem to be any clearer than a pair. However, I was bothered by the
fact that it was output in reverse order to the constructor args. How about
this?

[Ilya Sherman, 2015/06/29 22:05:34]

Yeah, I think that's a good compromise between clarity and density.  Thanks!

+}
+
 }  // namespace base