commit c1e6e8672a308a2719b0a5f679fc73931c7546e3
author Steve Anton <steveanton@webrtc.org> Mon Mar 04 14:43:44 2019 -0800
committer Commit Bot <commit-bot@chromium.org> Tue Mar 05 17:51:14 2019 +0000
tree b97be4463755cd28ea9a059e124c1752d876c142
parent d36c08623d9085dad821fbb1462a7fe03badcef5

Add metrics::Samples to facilitate easier testing

Currently, tests that verify metrics use a combination of
metrics::NumSamples and metrics::NumEvents to assert which samples
were recorded and how many times they were recorded. This means
that a comprehensive tests has n + 1 assertions for n distinct
samples.

The new metrics::Samples function returns a map of sample --> num
events which can be asserted against using gmock matchers,
achieving better coverage and better test failure messages in just
one line.

Bug: None
Change-Id: I07d4a766654cfc04e414b77b6de02927683a361f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/125486
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26974}

system_wrappers/source/metrics_unittest.cc

diff --git a/system_wrappers/source/metrics_unittest.cc b/system_wrappers/source/metrics_unittest.cc
index dac8177..9c96ba0 100644
--- a/system_wrappers/source/metrics_unittest.cc
+++ b/system_wrappers/source/metrics_unittest.cc
@@ -9,8 +9,13 @@
  */
 
 #include "system_wrappers/include/metrics.h"
+#include "test/gmock.h"
 #include "test/gtest.h"
 
+using ::testing::ElementsAre;
+using ::testing::IsEmpty;
+using ::testing::Pair;
+
 namespace webrtc {
 namespace {
 const int kSample = 22;
@@ -34,6 +39,7 @@
 TEST_F(MetricsTest, InitiallyNoSamples) {
   EXPECT_EQ(0, metrics::NumSamples("NonExisting"));
   EXPECT_EQ(0, metrics::NumEvents("NonExisting", kSample));
+  EXPECT_THAT(metrics::Samples("NonExisting"), IsEmpty());
 }
 
 TEST_F(MetricsTest, RtcHistogramPercent_AddSample) {
@@ -41,6 +47,7 @@
   RTC_HISTOGRAM_PERCENTAGE(kName, kSample);
   EXPECT_EQ(1, metrics::NumSamples(kName));
   EXPECT_EQ(1, metrics::NumEvents(kName, kSample));
+  EXPECT_THAT(metrics::Samples(kName), ElementsAre(Pair(kSample, 1)));
 }
 
 TEST_F(MetricsTest, RtcHistogramEnumeration_AddSample) {
@@ -48,6 +55,7 @@
   RTC_HISTOGRAM_ENUMERATION(kName, kSample, kSample + 1);
   EXPECT_EQ(1, metrics::NumSamples(kName));
   EXPECT_EQ(1, metrics::NumEvents(kName, kSample));
+  EXPECT_THAT(metrics::Samples(kName), ElementsAre(Pair(kSample, 1)));
 }
 
 TEST_F(MetricsTest, RtcHistogramBoolean_AddSample) {
@@ -56,6 +64,7 @@
   RTC_HISTOGRAM_BOOLEAN(kName, kSample);
   EXPECT_EQ(1, metrics::NumSamples(kName));
   EXPECT_EQ(1, metrics::NumEvents(kName, kSample));
+  EXPECT_THAT(metrics::Samples(kName), ElementsAre(Pair(kSample, 1)));
 }
 
 TEST_F(MetricsTest, RtcHistogramCountsSparse_AddSample) {
@@ -63,6 +72,7 @@
   RTC_HISTOGRAM_COUNTS_SPARSE_100(kName, kSample);
   EXPECT_EQ(1, metrics::NumSamples(kName));
   EXPECT_EQ(1, metrics::NumEvents(kName, kSample));
+  EXPECT_THAT(metrics::Samples(kName), ElementsAre(Pair(kSample, 1)));
 }
 
 TEST_F(MetricsTest, RtcHistogramCounts_AddSample) {
@@ -70,16 +80,20 @@
   RTC_HISTOGRAM_COUNTS_100(kName, kSample);
   EXPECT_EQ(1, metrics::NumSamples(kName));
   EXPECT_EQ(1, metrics::NumEvents(kName, kSample));
+  EXPECT_THAT(metrics::Samples(kName), ElementsAre(Pair(kSample, 1)));
 }
 
 TEST_F(MetricsTest, RtcHistogramCounts_AddMultipleSamples) {
   const std::string kName = "Counts200";
   const int kNumSamples = 10;
+  std::map<int, int> samples;
   for (int i = 1; i <= kNumSamples; ++i) {
     RTC_HISTOGRAM_COUNTS_200(kName, i);
     EXPECT_EQ(1, metrics::NumEvents(kName, i));
     EXPECT_EQ(i, metrics::NumSamples(kName));
+    samples[i] = 1;
   }
+  EXPECT_EQ(samples, metrics::Samples(kName));
 }
 
 TEST_F(MetricsTest, RtcHistogramsCounts_AddSample) {
@@ -92,6 +106,9 @@
   EXPECT_EQ(1, metrics::NumEvents("Name1", kSample + 0));
   EXPECT_EQ(1, metrics::NumEvents("Name2", kSample + 1));
   EXPECT_EQ(1, metrics::NumEvents("Name3", kSample + 2));
+  EXPECT_THAT(metrics::Samples("Name1"), ElementsAre(Pair(kSample + 0, 1)));
+  EXPECT_THAT(metrics::Samples("Name2"), ElementsAre(Pair(kSample + 1, 1)));
+  EXPECT_THAT(metrics::Samples("Name3"), ElementsAre(Pair(kSample + 2, 1)));
 }
 
 #if RTC_DCHECK_IS_ON && GTEST_HAS_DEATH_TEST && !defined(WEBRTC_ANDROID)
@@ -107,6 +124,8 @@
   AddSparseSample("Sparse2", kSample);
   EXPECT_EQ(1, metrics::NumSamples("Sparse1"));
   EXPECT_EQ(1, metrics::NumSamples("Sparse2"));
+  EXPECT_THAT(metrics::Samples("Sparse1"), ElementsAre(Pair(kSample, 1)));
+  EXPECT_THAT(metrics::Samples("Sparse2"), ElementsAre(Pair(kSample, 1)));
 }
 
 }  // namespace webrtc