remoting/base/rate_counter_unittest.cc

   1 // Copyright 2013 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 #include "remoting/base/rate_counter.h"
   6 #include "testing/gtest/include/gtest/gtest.h"
   7
   8 namespace remoting {
   9
  10 static const int64 kTestValues[] = { 10, 20, 30, 10, 25, 16, 15 };
  11
  12 // One second window and one sample per second, so rate equals each sample.
  13 TEST(RateCounterTest, OneSecondWindow) {
  14   RateCounter rate_counter(base::TimeDelta::FromSeconds(1));
  15   EXPECT_EQ(0, rate_counter.Rate());
  16
  17   base::Time now = base::Time::Now();
  18   for (size_t i = 0; i < arraysize(kTestValues); ++i) {
  19     now += base::TimeDelta::FromSeconds(1);
  20     rate_counter.SetCurrentTimeForTest(now);
  21     rate_counter.Record(kTestValues[i]);
  22     EXPECT_EQ(static_cast<double>(kTestValues[i]), rate_counter.Rate());
  23   }
  24 }
  25
  26 // Record all samples instantaneously, so the rate is the total of the samples.
  27 TEST(RateCounterTest, OneSecondWindowAllSamples) {
  28   RateCounter rate_counter(base::TimeDelta::FromSeconds(1));
  29   EXPECT_EQ(0, rate_counter.Rate());
  30
  31   rate_counter.SetCurrentTimeForTest(base::Time::Now());
  32
  33   double expected = 0.0;
  34   for (size_t i = 0; i < arraysize(kTestValues); ++i) {
  35     rate_counter.Record(kTestValues[i]);
  36     expected += kTestValues[i];
  37   }
  38
  39   EXPECT_EQ(expected, rate_counter.Rate());
  40 }
  41
  42 // Two second window, one sample per second.  For all but the first sample, the
  43 // rate should be the average of it and the preceding one.  For the first it
  44 // will be the average of the sample with zero.
  45 TEST(RateCounterTest, TwoSecondWindow) {
  46   RateCounter rate_counter(base::TimeDelta::FromSeconds(2));
  47   EXPECT_EQ(0, rate_counter.Rate());
  48
  49   base::Time now = base::Time::Now();
  50   for (size_t i = 0; i < arraysize(kTestValues); ++i) {
  51     now += base::TimeDelta::FromSeconds(1);
  52     rate_counter.SetCurrentTimeForTest(now);
  53     rate_counter.Record(kTestValues[i]);
  54     double expected = kTestValues[i];
  55     if (i > 0)
  56       expected += kTestValues[i-1];
  57     expected /= 2;
  58     EXPECT_EQ(expected, rate_counter.Rate());
  59   }
  60 }
  61
  62 // Sample over a window one second shorter than the number of samples.
  63 // Rate should be the average of all but the first sample.
  64 TEST(RateCounterTest, LongWindow) {
  65   const size_t kWindowSeconds = arraysize(kTestValues) - 1;
  66
  67   RateCounter rate_counter(base::TimeDelta::FromSeconds(kWindowSeconds));
  68   EXPECT_EQ(0, rate_counter.Rate());
  69
  70   double expected = 0.0;
  71   base::Time now = base::Time::Now();
  72   for (size_t i = 0; i < arraysize(kTestValues); ++i) {
  73     now += base::TimeDelta::FromSeconds(1);
  74     rate_counter.SetCurrentTimeForTest(now);
  75     rate_counter.Record(kTestValues[i]);
  76     if (i != 0)
  77       expected += kTestValues[i];
  78   }
  79   expected /= kWindowSeconds;
  80
  81   EXPECT_EQ(expected, rate_counter.Rate());
  82 }
  83
  84 }  // namespace remoting