shaka-packager/packager/mpd/base/bandwidth_estimator_unittes...

97 lines
3.0 KiB
C++

// Copyright 2014 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#include <gtest/gtest.h>
#include <cmath>
#include "packager/base/macros.h"
#include "packager/mpd/base/bandwidth_estimator.h"
namespace edash_packager {
namespace {
const int kNumBlocksForEstimate = 5;
const int kFirstOneBlockForEstimate = -1;
const uint64_t kBitsInByte = 8;
const int kEstimateRoundError = 1;
} // namespace
// Make sure that averaging of 5 blocks works, and also when there aren't all 5
// blocks.
TEST(BandwidthEstimatorTest, FiveBlocksFiveBlocksAdded) {
BandwidthEstimator be(kNumBlocksForEstimate);
const double kDuration = 1.0;
const uint64_t kExpectedResults[] = {
// Harmonic mean of [1 * 8], [1 * 8, 2 * 8], ...
// 8 is the number of bits in a byte and 1, 2, ... is from the loop
// counter below.
// Note that these are rounded up.
8,
11,
14,
16,
18
};
COMPILE_ASSERT(kNumBlocksForEstimate == arraysize(kExpectedResults),
incorrect_number_of_expectations);
for (uint64_t i = 1; i <= arraysize(kExpectedResults); ++i) {
be.AddBlock(i, kDuration);
EXPECT_EQ(kExpectedResults[i - 1], be.Estimate());
}
}
// More practical situation where a lot of blocks get added but only the last 5
// are considered for the estimate.
TEST(BandwidthEstimatorTest, FiveBlocksNormal) {
BandwidthEstimator be(kNumBlocksForEstimate);
const double kDuration = 10.0;
const uint64_t kNumBlocksToAdd = 200;
const uint64_t kExptectedEstimate = 800;
// Doesn't matter what gets passed to the estimator except for the last 5
// blocks which we add kExptectedEstimate / 8 bytes per second so that the
// estimate becomes kExptectedEstimate.
for (uint64_t i = 1; i <= kNumBlocksToAdd; ++i) {
if (i > kNumBlocksToAdd - kNumBlocksForEstimate) {
be.AddBlock(kExptectedEstimate * kDuration / kBitsInByte, kDuration);
} else {
be.AddBlock(i, kDuration);
}
}
EXPECT_NEAR(kExptectedEstimate, be.Estimate(), kEstimateRoundError);
}
// Average all the blocks!
TEST(BandwidthEstimatorTest, AllBlocks) {
BandwidthEstimator be(BandwidthEstimator::kUseAllBlocks);
const uint64_t kNumBlocksToAdd = 100;
const double kDuration = 1.0;
for (uint64_t i = 1; i <= kNumBlocksToAdd; ++i)
be.AddBlock(i, kDuration);
// The harmonic mean of 8, 16, ... , 800; rounded up.
const uint64_t kExptectedEstimate = 155;
EXPECT_EQ(kExptectedEstimate, be.Estimate());
}
// Use only the first one.
TEST(BandwidthEstimatorTest, FirstOneBlock) {
BandwidthEstimator be(kFirstOneBlockForEstimate);
const double kDuration = 11.0;
const uint64_t kExptectedEstimate = 123456;
be.AddBlock(kExptectedEstimate * kDuration / kBitsInByte, kDuration);
// Anything. Should be ignored.
for (int i = 0; i < 1000; ++i)
be.AddBlock(100000, 10);
EXPECT_EQ(kExptectedEstimate, be.Estimate());
}
} // namespace edash_packager