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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 #ifndef CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_ | |
6 #define CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_ | |
7 | |
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" | |
12 | |
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 | |
15 // intended. | |
16 class UMAHistogramHelper { | |
17 public: | |
18 // UMAHistogramHelper should be created before the execution of the test case. | |
19 UMAHistogramHelper(); | |
20 | |
21 ~UMAHistogramHelper(); | |
22 | |
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); | |
30 | |
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. | |
33 void Fetch(); | |
34 | |
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); | |
41 | |
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); | |
48 | |
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); | |
54 | |
55 private: | |
56 void FetchCallback(); | |
57 | |
58 void CheckBucketCount(const std::string& name, | |
59 base::HistogramBase::Sample sample, | |
60 base::Histogram::Count expected_count, | |
61 base::HistogramSamples& samples); | |
62 | |
63 void CheckTotalCount(const std::string& name, | |
64 base::Histogram::Count expected_count, | |
65 base::HistogramSamples& samples); | |
66 | |
67 DISALLOW_COPY_AND_ASSIGN(UMAHistogramHelper); | |
68 | |
69 // The map from histogram names to their snapshots | |
70 std::map<std::string, linked_ptr<base::HistogramSamples> > | |
71 histogram_snapshots; | |
72 }; | |
73 | |
74 #endif // CHROME_TEST_BASE_UMA_HISTOGRAM_HELPER_H_ | |
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