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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "quiche/quic/core/congestion_control/hybrid_slow_start.h"
#include <memory>
#include <utility>
#include "quiche/quic/platform/api/quic_test.h"
namespace quic {
namespace test {
class HybridSlowStartTest : public QuicTest {
protected:
HybridSlowStartTest()
: one_ms_(QuicTime::Delta::FromMilliseconds(1)),
rtt_(QuicTime::Delta::FromMilliseconds(60)) {}
void SetUp() override { slow_start_ = std::make_unique<HybridSlowStart>(); }
const QuicTime::Delta one_ms_;
const QuicTime::Delta rtt_;
std::unique_ptr<HybridSlowStart> slow_start_;
};
TEST_F(HybridSlowStartTest, Simple) {
QuicPacketNumber packet_number(1);
QuicPacketNumber end_packet_number(3);
slow_start_->StartReceiveRound(end_packet_number);
EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
// Test duplicates.
EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number));
EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
// Test without a new registered end_packet_number;
EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
end_packet_number = QuicPacketNumber(20);
slow_start_->StartReceiveRound(end_packet_number);
while (packet_number < end_packet_number) {
EXPECT_FALSE(slow_start_->IsEndOfRound(packet_number++));
}
EXPECT_TRUE(slow_start_->IsEndOfRound(packet_number++));
}
TEST_F(HybridSlowStartTest, Delay) {
// We expect to detect the increase at +1/8 of the RTT; hence at a typical
// RTT of 60ms the detection will happen at 67.5 ms.
const int kHybridStartMinSamples = 8; // Number of acks required to trigger.
QuicPacketNumber end_packet_number(1);
slow_start_->StartReceiveRound(end_packet_number++);
// Will not trigger since our lowest RTT in our burst is the same as the long
// term RTT provided.
for (int n = 0; n < kHybridStartMinSamples; ++n) {
EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
rtt_ + QuicTime::Delta::FromMilliseconds(n), rtt_, 100));
}
slow_start_->StartReceiveRound(end_packet_number++);
for (int n = 1; n < kHybridStartMinSamples; ++n) {
EXPECT_FALSE(slow_start_->ShouldExitSlowStart(
rtt_ + QuicTime::Delta::FromMilliseconds(n + 10), rtt_, 100));
}
// Expect to trigger since all packets in this burst was above the long term
// RTT provided.
EXPECT_TRUE(slow_start_->ShouldExitSlowStart(
rtt_ + QuicTime::Delta::FromMilliseconds(10), rtt_, 100));
}
} // namespace test
} // namespace quic