blob: d5a625127db995d6c78204af6227f8dcf3fc1eec [file] [log] [blame]
// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <math.h>
#include "chromecast/base/statistics/weighted_moving_average.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace chromecast {
TEST(WeightedMovingAverageTest, NoSamples) {
WeightedMovingAverage averager(0);
int64_t avg = 12345;
double error = 12345.0;
EXPECT_FALSE(averager.Average(&avg, &error));
EXPECT_EQ(12345, avg);
EXPECT_EQ(12345.0, error);
}
TEST(WeightedMovingAverageTest, ZeroWeight) {
WeightedMovingAverage averager(0);
for (int s = 1; s <= 5; ++s)
averager.AddSample(0, s, 0.0);
int64_t avg = 12345;
double error = 12345.0;
EXPECT_FALSE(averager.Average(&avg, &error));
EXPECT_EQ(12345, avg);
EXPECT_EQ(12345.0, error);
}
TEST(WeightedMovingAverageTest, AverageOneValue) {
int64_t value = 1;
WeightedMovingAverage averager(0);
averager.AddSample(0, value, 1.0);
int64_t avg = 0;
double error = 1.0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(value, avg);
EXPECT_EQ(0.0, error);
}
TEST(WeightedMovingAverageTest, AverageSeveralUnweightedValues) {
WeightedMovingAverage averager(0);
for (int s = 1; s <= 5; ++s)
averager.AddSample(0, s, 1.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(3, avg);
EXPECT_NEAR(sqrt(2) / sqrt(5), error, 1e-9);
}
TEST(WeightedMovingAverageTest, Clear) {
WeightedMovingAverage averager(0);
for (int s = 1; s <= 5; ++s)
averager.AddSample(0, s, 1.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(3, avg);
EXPECT_NEAR(sqrt(2) / sqrt(5), error, 1e-9);
averager.Clear();
EXPECT_FALSE(averager.Average(&avg, &error));
for (int s = 1; s <= 5; ++s)
averager.AddSample(0, s, 1.0);
avg = 0;
error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(3, avg);
EXPECT_NEAR(sqrt(2) / sqrt(5), error, 1e-9);
}
TEST(WeightedMovingAverageTest, AverageSeveralWeightedValues) {
WeightedMovingAverage averager(0);
averager.AddSample(0, 1, 2.0);
averager.AddSample(0, 2, 1.0);
averager.AddSample(0, 3, 0.0);
averager.AddSample(0, 4, 1.0);
averager.AddSample(0, 5, 2.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(3, avg);
// <sum of weights>^2 / <sum of weights^2>
double effective_sample_size = 36.0 / 10.0;
EXPECT_NEAR(sqrt(3) / sqrt(effective_sample_size), error, 1e-9);
}
TEST(WeightedMovingAverageTest, DropOldValues) {
WeightedMovingAverage averager(1);
for (int s = 0; s < 10; ++s)
averager.AddSample(s, 100, 5.0);
averager.AddSample(10, 1, 1.0);
averager.AddSample(11, 3, 1.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(2, avg);
EXPECT_DOUBLE_EQ(1.0 / sqrt(2), error);
}
TEST(WeightedMovingAverageTest, DropOldValuesUneven) {
WeightedMovingAverage averager(5);
for (int s = 0; s < 10; ++s)
averager.AddSample(s * s, 100, 5.0);
averager.AddSample(100, 1, 1.0);
averager.AddSample(105, 3, 1.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(2, avg);
EXPECT_DOUBLE_EQ(1.0 / sqrt(2), error);
}
TEST(WeightedMovingAverageTest, DropOldValuesByAddingZeroWeightValues) {
WeightedMovingAverage averager(5);
for (int s = 0; s < 10; ++s)
averager.AddSample(s, 1, 5.0);
// Adding values with weight 0 still drops old values.
for (int s = 11; s < 15; ++s)
averager.AddSample(s, 100, 0.0);
averager.AddSample(15, 10, 1.0);
int64_t avg = 0;
double error = 0;
EXPECT_TRUE(averager.Average(&avg, &error));
EXPECT_EQ(10, avg);
EXPECT_DOUBLE_EQ(0.0, error);
}
} // namespace chromecast