commit c081e369040bd46919f8d48607494780611442ac
author Sameer Abu Asal <sasal@google.com> Wed Feb 20 16:45:38 2013 -0800
committer Sameer Abu Asal <sasal@google.com> Wed Feb 20 16:45:38 2013 -0800
tree 6efab4fdeb94d891128595f02c6cfd1d2f1b83d8
parent 64f574f474aa77c72778640ab21f8cfa72546812

Improving histogram test cases

  Getting rid of the use or rand() in SpikyValues test cases to
  make the test deterministic.

  Improving accuracy for the histogram percentiles by selecting
  more restricted  lower and upper bound for a percentile.

Change-Id: If38750945e1980e8f637e836de02bee6f608e945

src/base/histogram_test.cc

diff --git a/src/base/histogram_test.cc b/src/base/histogram_test.cc
index 2adb41b..28812fd 100644
--- a/src/base/histogram_test.cc
+++ b/src/base/histogram_test.cc
@@ -31,7 +31,6 @@
   mean = hist->Mean();
   EXPECT_EQ(mean, 20.5);
 }
-;
 
 TEST(Histtest, VarianceTest) {
 
@@ -46,7 +45,6 @@
   EXPECT_EQ(variance, 64.25);
   delete hist;
 }
-;
 
 TEST(Histtest, Percentile) {
 
@@ -59,7 +57,9 @@
   hist->AddValue(50);
   hist->AddValue(60);
   hist->AddValue(70);
+
   hist->AddValue(98);
+
   hist->AddValue(110);
   hist->AddValue(121);
   hist->AddValue(132);
@@ -69,12 +69,10 @@
 
   hist->CreateHistogram();
   PerValue = hist->Percentile(0.50);
-  EXPECT_GE(PerValue, 70);
-  EXPECT_LE(PerValue, 110);
+  EXPECT_EQ(static_cast<int>(PerValue * 10), 875);
 
   delete hist;
 }
-;
 
 TEST(Histtest, UpdateRange) {
 
@@ -108,7 +106,7 @@
   std::string text;
   std::stringstream stream;
   std::string expected =
-      "UpdateRange:\t0.99% C.I. 15.262us-214.475us Avg: 126.380us Max: 212us\n";
+      "UpdateRange:\t0.99% C.I. 1.050us-214.475us Avg: 126.380us Max: 212us\n";
   hist->PrintConfidenceIntervals(stream, 0.99);
 
   EXPECT_EQ(expected, stream.str());
@@ -154,7 +152,7 @@
   std::string text;
   std::stringstream stream;
   std::string expected =
-      "Reset:\t0.99% C.I. 15.262us-214.475us Avg: 126.380us Max: 212us\n";
+      "Reset:\t0.99% C.I. 1.050us-214.475us Avg: 126.380us Max: 212us\n";
   hist->PrintConfidenceIntervals(stream, 0.99);
 
   EXPECT_EQ(expected, stream.str());
@@ -195,10 +193,9 @@
   hist->CreateHistogram();
   PerValue = hist->Percentile(0.50);
 
-  std::string text;
   std::stringstream stream;
   std::string expected =
-      "MultipleCreateHist:\t0.99% C.I. 15.262us-214.475us Avg: 126.380us Max: 212us\n";
+      "MultipleCreateHist:\t0.99% C.I. 1.050us-214.475us Avg: 126.380us Max: 212us\n";
   hist->PrintConfidenceIntervals(stream, 0.99);
 
   EXPECT_EQ(expected, stream.str());
@@ -207,46 +204,41 @@
 
   delete hist;
 }
-;
 
 TEST(Histtest, SingleValue) {
 
   Histogram<uint64_t> *hist = new Histogram<uint64_t>("SingleValue");
-  double PerValue_10;
-  double PerValue_90;
 
   hist->AddValue(1);
   hist->CreateHistogram();
-  PerValue_10 = hist->Percentile(0.1);
-  PerValue_90 = hist->Percentile(0.9);
 
-  EXPECT_GT(PerValue_10, 0);
-  EXPECT_LT(PerValue_90, 5);
+  std::stringstream stream;
+  std::string expected =
+      "SingleValue:\t0.99% C.I. 0.025us-4.975us Avg: 1us Max: 1us\n";
+  hist->PrintConfidenceIntervals(stream, 0.99);
+  EXPECT_EQ(stream.str(), expected);
 
   delete hist;
 }
-;
 
 TEST(Histtest, SpikyValues) {
 
   Histogram<uint64_t> *hist = new Histogram<uint64_t>("SpikyValues");
-  double PerValue_005;
-  double PerValue_995;
 
-  for (size_t Idx = 0; Idx < 300; Idx++) {
-    hist->AddValue(rand() % 200);
+  for (uint64_t idx = 0ull; idx < 30ull; idx++) {
+    for (uint64_t idx_inner = 0ull; idx_inner < 5ull; idx_inner++) {
+      hist->AddValue(idx * idx_inner);
+    }
   }
 
   hist->AddValue(10000);
   hist->CreateHistogram();
-  PerValue_005 = hist->Percentile(0.005);
-  PerValue_995 = hist->Percentile(0.995);
 
-  EXPECT_EQ(1.075, PerValue_005);
-  EXPECT_EQ(199747, static_cast<int>(PerValue_995 * 1000));
+  std::stringstream stream;
+  std::string expected =
+      "SpikyValues:\t0.99% C.I. 0.089us-2541.825us Avg: 95.033us Max: 10000us\n";
+  hist->PrintConfidenceIntervals(stream, 0.99);
+  EXPECT_EQ(stream.str(), expected);
+
   delete hist;
 }
-;
-
-
-