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.
5 #ifndef CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_
6 #define CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_
8 #include "base/memory/linked_ptr.h"
9 #include "base/metrics/histogram.h"
10 #include "base/metrics/histogram_base.h"
11 #include "base/metrics/histogram_samples.h"
13 // UMAHistogramHelper provides a simple interface for examining UMA histograms.
14 // Tests can use this interface to verify that UMA data is getting logged as
16 class UMAHistogramHelper {
18 // UMAHistogramHelper should be created before the execution of the test case.
21 ~UMAHistogramHelper();
23 // Parameters should be string literals of all histograms to snapshot.
24 // Call this before executing the test code. This method can be called
25 // multiple times. The existing snapshots are preserved, except when one of
26 // the |histogram_names| was previously passed as a parameter, then a new
27 // snapshot will replace the existing one.
28 void PrepareSnapshot(const char* const histogram_names[],
29 size_t num_histograms);
31 // Each child process may have its own histogram data, make sure this data
32 // gets accumulated into the browser process before we examine the histograms.
35 // We know the exact number of samples in a bucket, and that no other bucket
36 // should have samples. If |PrepareSnapshot| was called for the histogram
37 // named |name| then the |expected_count| is the diff from the snapshot.
38 void ExpectUniqueSample(const std::string& name,
39 base::HistogramBase::Sample sample,
40 base::HistogramBase::Count expected_count);
42 // We know the exact number of samples in a bucket, but other buckets may
43 // have samples as well. If |PrepareSnapshot| was called for histogram named
44 // |name| then the |expected_count| is the diff from the snapshot.
45 void ExpectBucketCount(const std::string& name,
46 base::HistogramBase::Sample sample,
47 base::HistogramBase::Count expected_count);
49 // We don't know the values of the samples, but we know how many there are. If
50 // |PrepareSnapshot| was called for |name| histogram, then the
51 // |count| is the diff from the snapshot.
52 void ExpectTotalCount(const std::string& name,
53 base::HistogramBase::Count count);
58 void CheckBucketCount(const std::string& name,
59 base::HistogramBase::Sample sample,
60 base::Histogram::Count expected_count,
61 base::HistogramSamples& samples);
63 void CheckTotalCount(const std::string& name,
64 base::Histogram::Count expected_count,
65 base::HistogramSamples& samples);
67 DISALLOW_COPY_AND_ASSIGN(UMAHistogramHelper);
69 // The map from histogram names to their snapshots
70 std::map<std::string, linked_ptr<base::HistogramSamples> >
74 #endif // CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_