| // 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. |
| |
| #ifndef BASE_TEST_HISTOGRAM_TESTER_H_ |
| #define BASE_TEST_HISTOGRAM_TESTER_H_ |
| |
| #include <map> |
| #include <string> |
| |
| #include "base/basictypes.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/metrics/histogram.h" |
| #include "base/metrics/histogram_base.h" |
| |
| namespace base { |
| |
| class HistogramSamples; |
| |
| // HistogramTester provides a simple interface for examining histograms, UMA |
| // or otherwise. Tests can use this interface to verify that histogram data is |
| // getting logged as intended. |
| class HistogramTester { |
| public: |
| // The constructor will call StatisticsRecorder::Initialize() for you. Also, |
| // this takes a snapshot of all current histograms counts. |
| HistogramTester(); |
| ~HistogramTester(); |
| |
| // We know the exact number of samples in a bucket, and that no other bucket |
| // should have samples. Measures the diff from the snapshot taken when this |
| // object was constructed. |
| void ExpectUniqueSample(const std::string& name, |
| base::HistogramBase::Sample sample, |
| base::HistogramBase::Count expected_count) const; |
| |
| // We know the exact number of samples in a bucket, but other buckets may |
| // have samples as well. Measures the diff from the snapshot taken when this |
| // object was constructed. |
| void ExpectBucketCount(const std::string& name, |
| base::HistogramBase::Sample sample, |
| base::HistogramBase::Count expected_count) const; |
| |
| // We don't know the values of the samples, but we know how many there are. |
| // This measures the diff from the snapshot taken when this object was |
| // constructed. |
| void ExpectTotalCount(const std::string& name, |
| base::HistogramBase::Count count) const; |
| |
| // Access a modified HistogramSamples containing only what has been logged |
| // to the histogram since the creation of this object. |
| scoped_ptr<HistogramSamples> GetHistogramSamplesSinceCreation( |
| const std::string& histogram_name); |
| |
| private: |
| // Verifies and asserts that value in the |sample| bucket matches the |
| // |expected_count|. The bucket's current value is determined from |samples| |
| // and is modified based on the snapshot stored for histogram |name|. |
| void CheckBucketCount(const std::string& name, |
| base::HistogramBase::Sample sample, |
| base::Histogram::Count expected_count, |
| const base::HistogramSamples& samples) const; |
| |
| // Verifies that the total number of values recorded for the histogram |name| |
| // is |expected_count|. This is checked against |samples| minus the snapshot |
| // that was taken for |name|. |
| void CheckTotalCount(const std::string& name, |
| base::Histogram::Count expected_count, |
| const base::HistogramSamples& samples) const; |
| |
| // Used to determine the histogram changes made during this instance's |
| // lifecycle. This instance takes ownership of the samples, which are deleted |
| // when the instance is destroyed. |
| std::map<std::string, HistogramSamples*> histograms_snapshot_; |
| |
| DISALLOW_COPY_AND_ASSIGN(HistogramTester); |
| }; |
| |
| } // namespace base |
| |
| #endif // BASE_TEST_HISTOGRAM_TESTER_H_ |