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      1 /*
      2  * libjingle
      3  * Copyright 2011, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/base/gunit.h"
     29 #include "talk/base/rollingaccumulator.h"
     30 
     31 namespace talk_base {
     32 
     33 namespace {
     34 
     35 const double kLearningRate = 0.5;
     36 
     37 }  // namespace
     38 
     39 TEST(RollingAccumulatorTest, ZeroSamples) {
     40   RollingAccumulator<int> accum(10);
     41 
     42   EXPECT_EQ(0U, accum.count());
     43   EXPECT_DOUBLE_EQ(0.0, accum.ComputeMean());
     44   EXPECT_DOUBLE_EQ(0.0, accum.ComputeVariance());
     45   EXPECT_EQ(0, accum.ComputeMin());
     46   EXPECT_EQ(0, accum.ComputeMax());
     47 }
     48 
     49 TEST(RollingAccumulatorTest, SomeSamples) {
     50   RollingAccumulator<int> accum(10);
     51   for (int i = 0; i < 4; ++i) {
     52     accum.AddSample(i);
     53   }
     54 
     55   EXPECT_EQ(4U, accum.count());
     56   EXPECT_EQ(6, accum.ComputeSum());
     57   EXPECT_DOUBLE_EQ(1.5, accum.ComputeMean());
     58   EXPECT_NEAR(2.26666, accum.ComputeWeightedMean(kLearningRate), 0.01);
     59   EXPECT_DOUBLE_EQ(1.25, accum.ComputeVariance());
     60   EXPECT_EQ(0, accum.ComputeMin());
     61   EXPECT_EQ(3, accum.ComputeMax());
     62 }
     63 
     64 TEST(RollingAccumulatorTest, RollingSamples) {
     65   RollingAccumulator<int> accum(10);
     66   for (int i = 0; i < 12; ++i) {
     67     accum.AddSample(i);
     68   }
     69 
     70   EXPECT_EQ(10U, accum.count());
     71   EXPECT_EQ(65, accum.ComputeSum());
     72   EXPECT_DOUBLE_EQ(6.5, accum.ComputeMean());
     73   EXPECT_NEAR(10.0, accum.ComputeWeightedMean(kLearningRate), 0.01);
     74   EXPECT_NEAR(9.0, accum.ComputeVariance(), 1.0);
     75   EXPECT_EQ(2, accum.ComputeMin());
     76   EXPECT_EQ(11, accum.ComputeMax());
     77 }
     78 
     79 TEST(RollingAccumulatorTest, ResetSamples) {
     80   RollingAccumulator<int> accum(10);
     81 
     82   for (int i = 0; i < 10; ++i) {
     83     accum.AddSample(100);
     84   }
     85   EXPECT_EQ(10U, accum.count());
     86   EXPECT_DOUBLE_EQ(100.0, accum.ComputeMean());
     87   EXPECT_EQ(100, accum.ComputeMin());
     88   EXPECT_EQ(100, accum.ComputeMax());
     89 
     90   accum.Reset();
     91   EXPECT_EQ(0U, accum.count());
     92 
     93   for (int i = 0; i < 5; ++i) {
     94     accum.AddSample(i);
     95   }
     96 
     97   EXPECT_EQ(5U, accum.count());
     98   EXPECT_EQ(10, accum.ComputeSum());
     99   EXPECT_DOUBLE_EQ(2.0, accum.ComputeMean());
    100   EXPECT_EQ(0, accum.ComputeMin());
    101   EXPECT_EQ(4, accum.ComputeMax());
    102 }
    103 
    104 TEST(RollingAccumulatorTest, RollingSamplesDouble) {
    105   RollingAccumulator<double> accum(10);
    106   for (int i = 0; i < 23; ++i) {
    107     accum.AddSample(5 * i);
    108   }
    109 
    110   EXPECT_EQ(10u, accum.count());
    111   EXPECT_DOUBLE_EQ(875.0, accum.ComputeSum());
    112   EXPECT_DOUBLE_EQ(87.5, accum.ComputeMean());
    113   EXPECT_NEAR(105.049, accum.ComputeWeightedMean(kLearningRate), 0.1);
    114   EXPECT_NEAR(229.166667, accum.ComputeVariance(), 25);
    115   EXPECT_DOUBLE_EQ(65.0, accum.ComputeMin());
    116   EXPECT_DOUBLE_EQ(110.0, accum.ComputeMax());
    117 }
    118 
    119 TEST(RollingAccumulatorTest, ComputeWeightedMeanCornerCases) {
    120   RollingAccumulator<int> accum(10);
    121   EXPECT_DOUBLE_EQ(0.0, accum.ComputeWeightedMean(kLearningRate));
    122   EXPECT_DOUBLE_EQ(0.0, accum.ComputeWeightedMean(0.0));
    123   EXPECT_DOUBLE_EQ(0.0, accum.ComputeWeightedMean(1.1));
    124 
    125   for (int i = 0; i < 8; ++i) {
    126     accum.AddSample(i);
    127   }
    128 
    129   EXPECT_DOUBLE_EQ(3.5, accum.ComputeMean());
    130   EXPECT_DOUBLE_EQ(3.5, accum.ComputeWeightedMean(0));
    131   EXPECT_DOUBLE_EQ(3.5, accum.ComputeWeightedMean(1.1));
    132   EXPECT_NEAR(6.0, accum.ComputeWeightedMean(kLearningRate), 0.1);
    133 }
    134 
    135 }  // namespace talk_base
    136