Expose macros from base/metrics/histogram_macros.h as functions

base/metrics/histogram_functions_unittest.cc

+// Copyright 2016 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/metrics/histogram_functions.h"
+
+#include "base/metrics/histogram_macros.h"
+#include "base/test/histogram_tester.h"
+#include "base/time/time.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+enum UmaHistogramTestingEnum {
+  UMA_HISTOGRAM_TESTING_ENUM_FIRST,
+  UMA_HISTOGRAM_TESTING_ENUM_SECOND,
+  UMA_HISTOGRAM_TESTING_ENUM_THIRD
+};
+
+TEST(HistogramFunctionsTest, HistogramExactLinear) {
+  std::string histogram("Testing.UMA.HistogramExactLinear");
+  HistogramTester tester;
+  UmaHistogramExactLinear(histogram, 10, 100);
+  tester.ExpectUniqueSample(histogram, 10, 1);
+  UmaHistogramExactLinear(histogram, 20, 100);
+  UmaHistogramExactLinear(histogram, 10, 100);
+  tester.ExpectBucketCount(histogram, 10, 2);
+  tester.ExpectBucketCount(histogram, 20, 1);
+  tester.ExpectTotalCount(histogram, 3);
+  // Test linear buckets overflow.
+  UmaHistogramExactLinear(histogram, 200, 100);
+  tester.ExpectBucketCount(histogram, 101, 1);
+  tester.ExpectTotalCount(histogram, 4);
+  // Test linear buckets underflow.
+  UmaHistogramExactLinear(histogram, 0, 100);
+  tester.ExpectBucketCount(histogram, 0, 1);
+  tester.ExpectTotalCount(histogram, 5);
+}
+
+TEST(HistogramFunctionsTest, HistogramEnumeration) {

[wychen, 2016/11/14 23:56:11]

Might worth adding some no-compile tests. Alas it is disabled by default.

+  std::string histogram("Testing.UMA.HistogramEnumeration");
+  HistogramTester tester;
+  UmaHistogramEnumeration(histogram, UMA_HISTOGRAM_TESTING_ENUM_FIRST,
+                          UMA_HISTOGRAM_TESTING_ENUM_THIRD);
+  tester.ExpectUniqueSample(histogram, UMA_HISTOGRAM_TESTING_ENUM_FIRST, 1);
+
+  // Verify the overflow & underflow bucket exists.
+  UMA_HISTOGRAM_ENUMERATION(
+      histogram, static_cast<int>(UMA_HISTOGRAM_TESTING_ENUM_THIRD) + 10,
+      UMA_HISTOGRAM_TESTING_ENUM_THIRD);
+  tester.ExpectBucketCount(
+      histogram, static_cast<int>(UMA_HISTOGRAM_TESTING_ENUM_THIRD) + 1, 1);
+  tester.ExpectTotalCount(histogram, 2);
+}
+
+TEST(HistogramFunctionsTest, HistogramBoolean) {
+  std::string histogram("Testing.UMA.HistogramBoolean");
+  HistogramTester tester;
+  UmaHistogramBoolean(histogram, true);
+  tester.ExpectUniqueSample(histogram, 1, 1);
+  UmaHistogramBoolean(histogram, false);
+  tester.ExpectBucketCount(histogram, 0, 1);
+  tester.ExpectTotalCount(histogram, 2);
+}
+
+TEST(HistogramFunctionsTest, HistogramPercentage) {
+  std::string histogram("Testing.UMA.HistogramPercentage");
+  HistogramTester tester;
+  UmaHistogramPercentage(histogram, 50);
+  tester.ExpectUniqueSample(histogram, 50, 1);
+  // Test overflows.
+  UmaHistogramPercentage(histogram, 110);
+  tester.ExpectBucketCount(histogram, 101, 1);
+  tester.ExpectTotalCount(histogram, 2);
+}
+
+TEST(HistogramFunctionsTest, HistogramCounts) {
+  std::string histogram("Testing.UMA.HistogramCount.Custom");
+  HistogramTester tester;
+  UmaHistogramCustomCounts(histogram, 10, 1, 100, 10);
+  tester.ExpectUniqueSample(histogram, 10, 1);
+  UmaHistogramCustomCounts(histogram, 20, 1, 100, 10);
+  UmaHistogramCustomCounts(histogram, 20, 1, 100, 10);
+  UmaHistogramCustomCounts(histogram, 20, 1, 100, 10);
+  tester.ExpectBucketCount(histogram, 20, 3);
+  tester.ExpectTotalCount(histogram, 4);
+  UmaHistogramCustomCounts(histogram, 110, 1, 100, 10);
+  tester.ExpectBucketCount(histogram, 101, 1);
+  tester.ExpectTotalCount(histogram, 5);
+}
+
+TEST(HistogramFunctionsTest, HistogramTimes) {
+  std::string histogram("Testing.UMA.HistogramTimes");
+  HistogramTester tester;
+  UmaHistogramTimes(histogram, TimeDelta::FromSeconds(1));
+  tester.ExpectTimeBucketCount(histogram, TimeDelta::FromSeconds(1), 1);
+  tester.ExpectTotalCount(histogram, 1);
+  UmaHistogramTimes(histogram, TimeDelta::FromSeconds(9));
+  tester.ExpectTimeBucketCount(histogram, TimeDelta::FromSeconds(9), 1);
+  tester.ExpectTotalCount(histogram, 2);
+  UmaHistogramTimes(histogram, TimeDelta::FromSeconds(10));  // Overflows
+  tester.ExpectTimeBucketCount(histogram, TimeDelta::FromSeconds(10), 1);
+  UmaHistogramTimes(histogram, TimeDelta::FromSeconds(20));  // Overflows.
+  // Check the value by picking any overflow time.
+  tester.ExpectTimeBucketCount(histogram, TimeDelta::FromSeconds(11), 2);
+  tester.ExpectTotalCount(histogram, 4);
+}
+
+}  // namespace base.