tests/daemon/fw/best-route-strategy2.t.cpp - NFD - Gitiles

 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
  * Copyright (c) 2014-2016,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
  *                           Washington University in St. Louis,
  *                           Beijing Institute of Technology,
  *                           The University of Memphis.
  *
  * This file is part of NFD (Named Data Networking Forwarding Daemon).
  * See AUTHORS.md for complete list of NFD authors and contributors.
  *
  * NFD is free software: you can redistribute it and/or modify it under the terms
  * of the GNU General Public License as published by the Free Software Foundation,
  * either version 3 of the License, or (at your option) any later version.
  *
  * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  * PURPOSE.  See the GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include "fw/best-route-strategy2.hpp"

 #include "tests/test-common.hpp"
 #include "tests/daemon/face/dummy-face.hpp"
 #include "strategy-tester.hpp"
 #include "topology-tester.hpp"

 namespace nfd {
 namespace fw {
 namespace tests {

 using namespace nfd::tests;

 typedef StrategyTester<BestRouteStrategy2> BestRouteStrategy2Tester;
 NFD_REGISTER_STRATEGY(BestRouteStrategy2Tester);

 BOOST_AUTO_TEST_SUITE(Fw)

 class BestRouteStrategy2Fixture : public UnitTestTimeFixture
 {
 protected:
   BestRouteStrategy2Fixture()
     : strategy(forwarder)
     , fib(forwarder.getFib())
     , pit(forwarder.getPit())
     , face1(make_shared<DummyFace>())
     , face2(make_shared<DummyFace>())
     , face3(make_shared<DummyFace>())
     , face4(make_shared<DummyFace>())
     , face5(make_shared<DummyFace>())
   {
     forwarder.addFace(face1);
     forwarder.addFace(face2);
     forwarder.addFace(face3);
     forwarder.addFace(face4);
     forwarder.addFace(face5);
   }

 public:
   Forwarder forwarder;
   BestRouteStrategy2Tester strategy;
   Fib& fib;
   Pit& pit;

   shared_ptr<DummyFace> face1;
   shared_ptr<DummyFace> face2;
   shared_ptr<DummyFace> face3;
   shared_ptr<DummyFace> face4;
   shared_ptr<DummyFace> face5;
 };

 BOOST_FIXTURE_TEST_SUITE(TestBestRouteStrategy2, BestRouteStrategy2Fixture)

 BOOST_AUTO_TEST_CASE(Forward)
 {
   fib::Entry& fibEntry = *fib.insert(Name()).first;
   fibEntry.addNextHop(*face1, 10);
   fibEntry.addNextHop(*face2, 20);
   fibEntry.addNextHop(*face3, 30);

   shared_ptr<Interest> interest = makeInterest("ndn:/BzgFBchqA");
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest).first;

   const time::nanoseconds TICK = time::duration_cast<time::nanoseconds>(
     BestRouteStrategy2::RETX_SUPPRESSION_INITIAL * 0.1);

   // first Interest goes to nexthop with lowest FIB cost,
   // however face1 is downstream so it cannot be used
   pitEntry->insertOrUpdateInRecord(*face1, *interest);
   strategy.afterReceiveInterest(*face1, *interest, pitEntry);
   BOOST_REQUIRE_EQUAL(strategy.sendInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory.back().outFaceId, face2->getId());

   // downstream retransmits frequently, but the strategy should not send Interests
   // more often than DEFAULT_MIN_RETX_INTERVAL
   scheduler::EventId retxFrom4Evt;
   size_t nSentLast = strategy.sendInterestHistory.size();
   time::steady_clock::TimePoint timeSentLast = time::steady_clock::now();
   function<void()> periodicalRetxFrom4; // let periodicalRetxFrom4 lambda capture itself
   periodicalRetxFrom4 = [&] {
     pitEntry->insertOrUpdateInRecord(*face4, *interest);
     strategy.afterReceiveInterest(*face4, *interest, pitEntry);

     size_t nSent = strategy.sendInterestHistory.size();
     if (nSent > nSentLast) {
       BOOST_CHECK_EQUAL(nSent - nSentLast, 1);
       time::steady_clock::TimePoint timeSent = time::steady_clock::now();
       BOOST_CHECK_GE(timeSent - timeSentLast, TICK * 8);
       nSentLast = nSent;
       timeSentLast = timeSent;
     }

     retxFrom4Evt = scheduler::schedule(TICK * 5, periodicalRetxFrom4);
   };
   periodicalRetxFrom4();
   this->advanceClocks(TICK, BestRouteStrategy2::RETX_SUPPRESSION_MAX * 16);
   scheduler::cancel(retxFrom4Evt);

   // nexthops for accepted retransmissions: follow FIB cost,
   // later forward to an eligible upstream with earliest out-record
   BOOST_REQUIRE_GE(strategy.sendInterestHistory.size(), 6);
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory[1].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory[2].outFaceId, face3->getId());
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory[3].outFaceId, face2->getId());
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory[4].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy.sendInterestHistory[5].outFaceId, face3->getId());

   fibEntry.removeNextHop(*face1);

   strategy.sendInterestHistory.clear();
   for (int i = 0; i < 3; ++i) {
     this->advanceClocks(TICK, BestRouteStrategy2::RETX_SUPPRESSION_MAX * 2);
     pitEntry->insertOrUpdateInRecord(*face5, *interest);
     strategy.afterReceiveInterest(*face5, *interest, pitEntry);
   }
   BOOST_REQUIRE_EQUAL(strategy.sendInterestHistory.size(), 3);
   BOOST_CHECK_NE(strategy.sendInterestHistory[0].outFaceId, face1->getId());
   BOOST_CHECK_NE(strategy.sendInterestHistory[1].outFaceId, face1->getId());
   BOOST_CHECK_NE(strategy.sendInterestHistory[2].outFaceId, face1->getId());
   // face1 cannot be used because it's gone from FIB entry
 }

 BOOST_AUTO_TEST_SUITE(NoRouteNack) // send Nack-NoRoute if there's no usable FIB nexthop

 class EmptyNextHopList
 {
 public:
   Name
   getInterestName()
   {
     return "/P";
   }

   void
   insertFibEntry(BestRouteStrategy2Fixture* fixture)
   {
     fixture->fib.insert(Name());
   }
 };

 class NextHopIsDownstream
 {
 public:
   Name
   getInterestName()
   {
     return "/P";
   }

   void
   insertFibEntry(BestRouteStrategy2Fixture* fixture)
   {
     fixture->fib.insert(Name()).first->addNextHop(*fixture->face1, 10);
   }
 };

 class NextHopViolatesScope
 {
 public:
   Name
   getInterestName()
   {
     return "/localhop/P";
   }

   void
   insertFibEntry(BestRouteStrategy2Fixture* fixture)
   {
     fixture->fib.insert("/localhop").first->addNextHop(*fixture->face2, 10);
     // face1 and face2 are both non-local; Interest from face1 cannot be forwarded to face2
   }
 };

 typedef boost::mpl::vector<EmptyNextHopList, NextHopIsDownstream, NextHopViolatesScope> NoRouteScenarios;

 BOOST_AUTO_TEST_CASE_TEMPLATE(IncomingInterest, Scenario, NoRouteScenarios)
 {
   Scenario scenario;
   scenario.insertFibEntry(this);

   shared_ptr<Interest> interest = makeInterest(scenario.getInterestName());
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest).first;
   pitEntry->insertOrUpdateInRecord(*face1, *interest);

   strategy.afterReceiveInterest(*face1, *interest, pitEntry);

   BOOST_REQUIRE_EQUAL(strategy.rejectPendingInterestHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy.rejectPendingInterestHistory[0].pitInterest, pitEntry->getInterest());

   BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::NO_ROUTE);
 }

 BOOST_AUTO_TEST_SUITE_END() // NoRouteNack

 BOOST_AUTO_TEST_SUITE(IncomingNack)

 BOOST_AUTO_TEST_CASE(OneUpstream) // one upstream, send Nack when Nack arrives
 {
   fib::Entry& fibEntry = *fib.insert(Name()).first;
   fibEntry.addNextHop(*face3, 10);
   fibEntry.addNextHop(*face4, 20);
   fibEntry.addNextHop(*face5, 30);

   shared_ptr<Interest> interest1 = makeInterest("/McQYjMbm", 992);
   shared_ptr<Interest> interest2 = makeInterest("/McQYjMbm", 114);
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
   pitEntry->insertOrUpdateInRecord(*face1, *interest1);
   pitEntry->insertOrUpdateInRecord(*face2, *interest2);
   pitEntry->insertOrUpdateOutRecord(*face3, *interest1);

   lp::Nack nack3 = makeNack("/McQYjMbm", 992, lp::NackReason::CONGESTION);
   pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
   strategy.afterReceiveNack(*face3, nack3, pitEntry);

   BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 2);
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::CONGESTION);
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[1].pitInterest, pitEntry->getInterest());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[1].header.getReason(), lp::NackReason::CONGESTION);
   std::unordered_set<FaceId> nackFaceIds{strategy.sendNackHistory[0].outFaceId,
                                          strategy.sendNackHistory[1].outFaceId};
   std::unordered_set<FaceId> expectedNackFaceIds{face1->getId(), face2->getId()};
   BOOST_CHECK_EQUAL_COLLECTIONS(nackFaceIds.begin(), nackFaceIds.end(),
                                 expectedNackFaceIds.begin(), expectedNackFaceIds.end());
 }

 BOOST_AUTO_TEST_CASE(TwoUpstreams) // two upstreams, send Nack when both Nacks arrive
 {
   fib::Entry& fibEntry = *fib.insert(Name()).first;
   fibEntry.addNextHop(*face3, 10);
   fibEntry.addNextHop(*face4, 20);
   fibEntry.addNextHop(*face5, 30);

   shared_ptr<Interest> interest1 = makeInterest("/aS9FAyUV19", 286);
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
   pitEntry->insertOrUpdateInRecord(*face1, *interest1);
   pitEntry->insertOrUpdateOutRecord(*face3, *interest1);
   pitEntry->insertOrUpdateOutRecord(*face4, *interest1);

   lp::Nack nack3 = makeNack("/aS9FAyUV19", 286, lp::NackReason::CONGESTION);
   pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
   strategy.afterReceiveNack(*face3, nack3, pitEntry);

   BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0); // don't send Nack until all upstreams have Nacked

   lp::Nack nack4 = makeNack("/aS9FAyUV19", 286, lp::NackReason::CONGESTION);
   pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
   strategy.afterReceiveNack(*face4, nack4, pitEntry);

   BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::CONGESTION);
 }

 BOOST_AUTO_TEST_CASE(Timeout) // two upstreams, one times out, don't send Nack
 {
   fib::Entry& fibEntry = *fib.insert(Name()).first;
   fibEntry.addNextHop(*face3, 10);
   fibEntry.addNextHop(*face4, 20);
   fibEntry.addNextHop(*face5, 30);

   shared_ptr<Interest> interest1 = makeInterest("/sIYw0TXWDj", 115);
   interest1->setInterestLifetime(time::milliseconds(400));
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
   pitEntry->insertOrUpdateInRecord(*face1, *interest1);
   pitEntry->insertOrUpdateOutRecord(*face3, *interest1);

   this->advanceClocks(time::milliseconds(300));
   shared_ptr<Interest> interest2 = makeInterest("/sIYw0TXWDj", 223);
   pitEntry->insertOrUpdateInRecord(*face1, *interest2);
   pitEntry->insertOrUpdateOutRecord(*face4, *interest2);

   this->advanceClocks(time::milliseconds(200)); // face3 has timed out

   lp::Nack nack4 = makeNack("/sIYw0TXWDj", 223, lp::NackReason::CONGESTION);
   pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
   strategy.afterReceiveNack(*face4, nack4, pitEntry);

   BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0);
 }

 BOOST_FIXTURE_TEST_CASE(LiveDeadlock, UnitTestTimeFixture) // #3033 note-7
 {
   /*
    *           /----------\
    *           | producer |
    *           \----------/
    *                |
    *              +---+
    *              | P |
    *              +---+
    *                |
    *           failed link
    *                |
    *              +---+
    *              | R |
    *              +---+
    *             ^     ^
    *            /       \
    *           /         \
    *        +---+       +---+
    *        | B | <---> | C |
    *        +---+       +---+
    *          ^           ^
    *          |           |
    *          |           |
    *        +---+       +---+
    *        | A |       | D |
    *        +---+       +---+
    *          ^           ^
    *          |           |
    *  /----------\     /----------\
    *  | consumer |     | consumer |
    *  \----------/     \----------/
    */

   TopologyTester topo;
   TopologyNode nodeP = topo.addForwarder("P"),
                nodeR = topo.addForwarder("R"),
                nodeA = topo.addForwarder("A"),
                nodeB = topo.addForwarder("B"),
                nodeC = topo.addForwarder("C"),
                nodeD = topo.addForwarder("D");

   for (TopologyNode node : {nodeP, nodeR, nodeA, nodeB, nodeC, nodeD}) {
     topo.setStrategy<BestRouteStrategy2>(node);
   }

   const time::milliseconds LINK_DELAY(10);
   shared_ptr<TopologyLink> linkPR = topo.addLink("PR", LINK_DELAY, {nodeP, nodeR}),
                            linkRB = topo.addLink("RB", LINK_DELAY, {nodeR, nodeB}),
                            linkRC = topo.addLink("RC", LINK_DELAY, {nodeR, nodeC}),
                            linkBC = topo.addLink("BC", LINK_DELAY, {nodeB, nodeC}),
                            linkBA = topo.addLink("BA", LINK_DELAY, {nodeB, nodeA}),
                            linkCD = topo.addLink("CD", LINK_DELAY, {nodeC, nodeD});

   // TODO register the prefix on R->P but then set the face DOWN
   // topo.registerPrefix(nodeR, linkPR->getFace(nodeR), "ndn:/P", 10);
   topo.registerPrefix(nodeB, linkRB->getFace(nodeB), "ndn:/P", 20);
   topo.registerPrefix(nodeB, linkBC->getFace(nodeB), "ndn:/P", 30);
   topo.registerPrefix(nodeC, linkRC->getFace(nodeC), "ndn:/P", 20);
   topo.registerPrefix(nodeC, linkBC->getFace(nodeC), "ndn:/P", 30);
   topo.registerPrefix(nodeA, linkBA->getFace(nodeA), "ndn:/P", 30);
   topo.registerPrefix(nodeD, linkCD->getFace(nodeD), "ndn:/P", 30);

   ndn::Face& appA = topo.addAppFace("A", nodeA)->getClientFace();
   ndn::Face& appD = topo.addAppFace("D", nodeD)->getClientFace();

   int nNacksA = 0, nNacksD = 0;
   appA.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksA]{ ++nNacksA; }), bind([]{}));
   appD.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksD]{ ++nNacksD; }), bind([]{}));
   this->advanceClocks(time::milliseconds(1), time::milliseconds(5));
   appA.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksA]{ ++nNacksA; }), bind([]{}));
   appD.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksD]{ ++nNacksD; }), bind([]{}));
   this->advanceClocks(time::milliseconds(1), time::milliseconds(100));

   // As long as at least one Nack arrives at each client, strategy behavior is correct.
   // Whether both Interests are Nacked is a client face behavior, not strategy behavior.
   BOOST_CHECK_GT(nNacksA, 0);
   BOOST_CHECK_GT(nNacksD, 0);
 }

 template<lp::NackReason X, lp::NackReason Y, lp::NackReason R>
 struct NackReasonCombination
 {
   lp::NackReason
   getX() const
   {
     return X;
   }

   lp::NackReason
   getY() const
   {
     return Y;
   }

   lp::NackReason
   getExpectedResult() const
   {
     return R;
   }
 };

 typedef boost::mpl::vector<
     NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
     NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::DUPLICATE, lp::NackReason::CONGESTION>,
     NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::NO_ROUTE, lp::NackReason::CONGESTION>,
     NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
     NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE>,
     NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::NO_ROUTE, lp::NackReason::DUPLICATE>,
     NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
     NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE>,
     NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::NO_ROUTE, lp::NackReason::NO_ROUTE>
   > NackReasonCombinations;

 BOOST_AUTO_TEST_CASE_TEMPLATE(CombineReasons, Combination, NackReasonCombinations)
 {
   Combination combination;

   fib::Entry& fibEntry = *fib.insert(Name()).first;
   fibEntry.addNextHop(*face3, 10);
   fibEntry.addNextHop(*face4, 20);
   fibEntry.addNextHop(*face5, 30);

   shared_ptr<Interest> interest1 = makeInterest("/F6sEwB24I", 282);
   shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
   pitEntry->insertOrUpdateInRecord(*face1, *interest1);
   pitEntry->insertOrUpdateOutRecord(*face3, *interest1);
   pitEntry->insertOrUpdateOutRecord(*face4, *interest1);

   lp::Nack nack3 = makeNack("/F6sEwB24I", 282, combination.getX());
   pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
   strategy.afterReceiveNack(*face3, nack3, pitEntry);

   BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0);

   lp::Nack nack4 = makeNack("/F6sEwB24I", 282, combination.getY());
   pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
   strategy.afterReceiveNack(*face4, nack4, pitEntry);

   BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
   BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), combination.getExpectedResult());
 }

 BOOST_AUTO_TEST_SUITE_END() // IncomingNack

 BOOST_AUTO_TEST_SUITE_END() // TestBestRouteStrategy2
 BOOST_AUTO_TEST_SUITE_END() // Fw

 } // namespace tests
 } // namespace fw
 } // namespace nfd
	/* -- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -- */
	/**
	* Copyright (c) 2014-2016, Regents of the University of California,
	* Arizona Board of Regents,
	* Colorado State University,
	* University Pierre & Marie Curie, Sorbonne University,
	* Washington University in St. Louis,
	* Beijing Institute of Technology,
	* The University of Memphis.
	*
	* This file is part of NFD (Named Data Networking Forwarding Daemon).
	* See AUTHORS.md for complete list of NFD authors and contributors.
	*
	* NFD is free software: you can redistribute it and/or modify it under the terms
	* of the GNU General Public License as published by the Free Software Foundation,
	* either version 3 of the License, or (at your option) any later version.
	*
	* NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
	* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
	* PURPOSE. See the GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* NFD, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "fw/best-route-strategy2.hpp"

	#include "tests/test-common.hpp"
	#include "tests/daemon/face/dummy-face.hpp"
	#include "strategy-tester.hpp"
	#include "topology-tester.hpp"

	namespace nfd {
	namespace fw {
	namespace tests {

	using namespace nfd::tests;

	typedef StrategyTester<BestRouteStrategy2> BestRouteStrategy2Tester;
	NFD_REGISTER_STRATEGY(BestRouteStrategy2Tester);

	BOOST_AUTO_TEST_SUITE(Fw)

	class BestRouteStrategy2Fixture : public UnitTestTimeFixture
	{
	protected:
	BestRouteStrategy2Fixture()
	: strategy(forwarder)
	, fib(forwarder.getFib())
	, pit(forwarder.getPit())
	, face1(make_shared<DummyFace>())
	, face2(make_shared<DummyFace>())
	, face3(make_shared<DummyFace>())
	, face4(make_shared<DummyFace>())
	, face5(make_shared<DummyFace>())
	{
	forwarder.addFace(face1);
	forwarder.addFace(face2);
	forwarder.addFace(face3);
	forwarder.addFace(face4);
	forwarder.addFace(face5);
	}

	public:
	Forwarder forwarder;
	BestRouteStrategy2Tester strategy;
	Fib& fib;
	Pit& pit;

	shared_ptr<DummyFace> face1;
	shared_ptr<DummyFace> face2;
	shared_ptr<DummyFace> face3;
	shared_ptr<DummyFace> face4;
	shared_ptr<DummyFace> face5;
	};

	BOOST_FIXTURE_TEST_SUITE(TestBestRouteStrategy2, BestRouteStrategy2Fixture)

	BOOST_AUTO_TEST_CASE(Forward)
	{
	fib::Entry& fibEntry = *fib.insert(Name()).first;
	fibEntry.addNextHop(*face1, 10);
	fibEntry.addNextHop(*face2, 20);
	fibEntry.addNextHop(*face3, 30);

	shared_ptr<Interest> interest = makeInterest("ndn:/BzgFBchqA");
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest).first;

	const time::nanoseconds TICK = time::duration_cast<time::nanoseconds>(
	BestRouteStrategy2::RETX_SUPPRESSION_INITIAL * 0.1);

	// first Interest goes to nexthop with lowest FIB cost,
	// however face1 is downstream so it cannot be used
	pitEntry->insertOrUpdateInRecord(face1, interest);
	strategy.afterReceiveInterest(face1, interest, pitEntry);
	BOOST_REQUIRE_EQUAL(strategy.sendInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory.back().outFaceId, face2->getId());

	// downstream retransmits frequently, but the strategy should not send Interests
	// more often than DEFAULT_MIN_RETX_INTERVAL
	scheduler::EventId retxFrom4Evt;
	size_t nSentLast = strategy.sendInterestHistory.size();
	time::steady_clock::TimePoint timeSentLast = time::steady_clock::now();
	function<void()> periodicalRetxFrom4; // let periodicalRetxFrom4 lambda capture itself
	periodicalRetxFrom4 = [&] {
	pitEntry->insertOrUpdateInRecord(face4, interest);
	strategy.afterReceiveInterest(face4, interest, pitEntry);

	size_t nSent = strategy.sendInterestHistory.size();
	if (nSent > nSentLast) {
	BOOST_CHECK_EQUAL(nSent - nSentLast, 1);
	time::steady_clock::TimePoint timeSent = time::steady_clock::now();
	BOOST_CHECK_GE(timeSent - timeSentLast, TICK * 8);
	nSentLast = nSent;
	timeSentLast = timeSent;
	}

	retxFrom4Evt = scheduler::schedule(TICK * 5, periodicalRetxFrom4);
	};
	periodicalRetxFrom4();
	this->advanceClocks(TICK, BestRouteStrategy2::RETX_SUPPRESSION_MAX * 16);
	scheduler::cancel(retxFrom4Evt);

	// nexthops for accepted retransmissions: follow FIB cost,
	// later forward to an eligible upstream with earliest out-record
	BOOST_REQUIRE_GE(strategy.sendInterestHistory.size(), 6);
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory[1].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory[2].outFaceId, face3->getId());
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory[3].outFaceId, face2->getId());
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory[4].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy.sendInterestHistory[5].outFaceId, face3->getId());

	fibEntry.removeNextHop(*face1);

	strategy.sendInterestHistory.clear();
	for (int i = 0; i < 3; ++i) {
	this->advanceClocks(TICK, BestRouteStrategy2::RETX_SUPPRESSION_MAX * 2);
	pitEntry->insertOrUpdateInRecord(face5, interest);
	strategy.afterReceiveInterest(face5, interest, pitEntry);
	}
	BOOST_REQUIRE_EQUAL(strategy.sendInterestHistory.size(), 3);
	BOOST_CHECK_NE(strategy.sendInterestHistory[0].outFaceId, face1->getId());
	BOOST_CHECK_NE(strategy.sendInterestHistory[1].outFaceId, face1->getId());
	BOOST_CHECK_NE(strategy.sendInterestHistory[2].outFaceId, face1->getId());
	// face1 cannot be used because it's gone from FIB entry
	}

	BOOST_AUTO_TEST_SUITE(NoRouteNack) // send Nack-NoRoute if there's no usable FIB nexthop

	class EmptyNextHopList
	{
	public:
	Name
	getInterestName()
	{
	return "/P";
	}

	void
	insertFibEntry(BestRouteStrategy2Fixture* fixture)
	{
	fixture->fib.insert(Name());
	}
	};

	class NextHopIsDownstream
	{
	public:
	Name
	getInterestName()
	{
	return "/P";
	}

	void
	insertFibEntry(BestRouteStrategy2Fixture* fixture)
	{
	fixture->fib.insert(Name()).first->addNextHop(*fixture->face1, 10);
	}
	};

	class NextHopViolatesScope
	{
	public:
	Name
	getInterestName()
	{
	return "/localhop/P";
	}

	void
	insertFibEntry(BestRouteStrategy2Fixture* fixture)
	{
	fixture->fib.insert("/localhop").first->addNextHop(*fixture->face2, 10);
	// face1 and face2 are both non-local; Interest from face1 cannot be forwarded to face2
	}
	};

	typedef boost::mpl::vector<EmptyNextHopList, NextHopIsDownstream, NextHopViolatesScope> NoRouteScenarios;

	BOOST_AUTO_TEST_CASE_TEMPLATE(IncomingInterest, Scenario, NoRouteScenarios)
	{
	Scenario scenario;
	scenario.insertFibEntry(this);

	shared_ptr<Interest> interest = makeInterest(scenario.getInterestName());
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest).first;
	pitEntry->insertOrUpdateInRecord(face1, interest);

	strategy.afterReceiveInterest(face1, interest, pitEntry);

	BOOST_REQUIRE_EQUAL(strategy.rejectPendingInterestHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy.rejectPendingInterestHistory[0].pitInterest, pitEntry->getInterest());

	BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::NO_ROUTE);
	}

	BOOST_AUTO_TEST_SUITE_END() // NoRouteNack

	BOOST_AUTO_TEST_SUITE(IncomingNack)

	BOOST_AUTO_TEST_CASE(OneUpstream) // one upstream, send Nack when Nack arrives
	{
	fib::Entry& fibEntry = *fib.insert(Name()).first;
	fibEntry.addNextHop(*face3, 10);
	fibEntry.addNextHop(*face4, 20);
	fibEntry.addNextHop(*face5, 30);

	shared_ptr<Interest> interest1 = makeInterest("/McQYjMbm", 992);
	shared_ptr<Interest> interest2 = makeInterest("/McQYjMbm", 114);
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
	pitEntry->insertOrUpdateInRecord(face1, interest1);
	pitEntry->insertOrUpdateInRecord(face2, interest2);
	pitEntry->insertOrUpdateOutRecord(face3, interest1);

	lp::Nack nack3 = makeNack("/McQYjMbm", 992, lp::NackReason::CONGESTION);
	pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
	strategy.afterReceiveNack(*face3, nack3, pitEntry);

	BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 2);
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::CONGESTION);
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[1].pitInterest, pitEntry->getInterest());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[1].header.getReason(), lp::NackReason::CONGESTION);
	std::unordered_set<FaceId> nackFaceIds{strategy.sendNackHistory[0].outFaceId,
	strategy.sendNackHistory[1].outFaceId};
	std::unordered_set<FaceId> expectedNackFaceIds{face1->getId(), face2->getId()};
	BOOST_CHECK_EQUAL_COLLECTIONS(nackFaceIds.begin(), nackFaceIds.end(),
	expectedNackFaceIds.begin(), expectedNackFaceIds.end());
	}

	BOOST_AUTO_TEST_CASE(TwoUpstreams) // two upstreams, send Nack when both Nacks arrive
	{
	fib::Entry& fibEntry = *fib.insert(Name()).first;
	fibEntry.addNextHop(*face3, 10);
	fibEntry.addNextHop(*face4, 20);
	fibEntry.addNextHop(*face5, 30);

	shared_ptr<Interest> interest1 = makeInterest("/aS9FAyUV19", 286);
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
	pitEntry->insertOrUpdateInRecord(face1, interest1);
	pitEntry->insertOrUpdateOutRecord(face3, interest1);
	pitEntry->insertOrUpdateOutRecord(face4, interest1);

	lp::Nack nack3 = makeNack("/aS9FAyUV19", 286, lp::NackReason::CONGESTION);
	pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
	strategy.afterReceiveNack(*face3, nack3, pitEntry);

	BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0); // don't send Nack until all upstreams have Nacked

	lp::Nack nack4 = makeNack("/aS9FAyUV19", 286, lp::NackReason::CONGESTION);
	pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
	strategy.afterReceiveNack(*face4, nack4, pitEntry);

	BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), lp::NackReason::CONGESTION);
	}

	BOOST_AUTO_TEST_CASE(Timeout) // two upstreams, one times out, don't send Nack
	{
	fib::Entry& fibEntry = *fib.insert(Name()).first;
	fibEntry.addNextHop(*face3, 10);
	fibEntry.addNextHop(*face4, 20);
	fibEntry.addNextHop(*face5, 30);

	shared_ptr<Interest> interest1 = makeInterest("/sIYw0TXWDj", 115);
	interest1->setInterestLifetime(time::milliseconds(400));
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
	pitEntry->insertOrUpdateInRecord(face1, interest1);
	pitEntry->insertOrUpdateOutRecord(face3, interest1);

	this->advanceClocks(time::milliseconds(300));
	shared_ptr<Interest> interest2 = makeInterest("/sIYw0TXWDj", 223);
	pitEntry->insertOrUpdateInRecord(face1, interest2);
	pitEntry->insertOrUpdateOutRecord(face4, interest2);

	this->advanceClocks(time::milliseconds(200)); // face3 has timed out

	lp::Nack nack4 = makeNack("/sIYw0TXWDj", 223, lp::NackReason::CONGESTION);
	pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
	strategy.afterReceiveNack(*face4, nack4, pitEntry);

	BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0);
	}

	BOOST_FIXTURE_TEST_CASE(LiveDeadlock, UnitTestTimeFixture) // #3033 note-7
	{
	/*
	* /----------\
	* \| producer \|
	* \----------/
	* \|
	* +---+
	* \| P \|
	* +---+
	* \|
	* failed link
	* \|
	* +---+
	* \| R \|
	* +---+
	* ^ ^
	* / \
	* / \
	* +---+ +---+
	* \| B \| <---> \| C \|
	* +---+ +---+
	* ^ ^
	* \| \|
	* \| \|
	* +---+ +---+
	* \| A \| \| D \|
	* +---+ +---+
	* ^ ^
	* \| \|
	* /----------\ /----------\
	* \| consumer \| \| consumer \|
	* \----------/ \----------/
	*/

	TopologyTester topo;
	TopologyNode nodeP = topo.addForwarder("P"),
	nodeR = topo.addForwarder("R"),
	nodeA = topo.addForwarder("A"),
	nodeB = topo.addForwarder("B"),
	nodeC = topo.addForwarder("C"),
	nodeD = topo.addForwarder("D");

	for (TopologyNode node : {nodeP, nodeR, nodeA, nodeB, nodeC, nodeD}) {
	topo.setStrategy<BestRouteStrategy2>(node);
	}

	const time::milliseconds LINK_DELAY(10);
	shared_ptr<TopologyLink> linkPR = topo.addLink("PR", LINK_DELAY, {nodeP, nodeR}),
	linkRB = topo.addLink("RB", LINK_DELAY, {nodeR, nodeB}),
	linkRC = topo.addLink("RC", LINK_DELAY, {nodeR, nodeC}),
	linkBC = topo.addLink("BC", LINK_DELAY, {nodeB, nodeC}),
	linkBA = topo.addLink("BA", LINK_DELAY, {nodeB, nodeA}),
	linkCD = topo.addLink("CD", LINK_DELAY, {nodeC, nodeD});

	// TODO register the prefix on R->P but then set the face DOWN
	// topo.registerPrefix(nodeR, linkPR->getFace(nodeR), "ndn:/P", 10);
	topo.registerPrefix(nodeB, linkRB->getFace(nodeB), "ndn:/P", 20);
	topo.registerPrefix(nodeB, linkBC->getFace(nodeB), "ndn:/P", 30);
	topo.registerPrefix(nodeC, linkRC->getFace(nodeC), "ndn:/P", 20);
	topo.registerPrefix(nodeC, linkBC->getFace(nodeC), "ndn:/P", 30);
	topo.registerPrefix(nodeA, linkBA->getFace(nodeA), "ndn:/P", 30);
	topo.registerPrefix(nodeD, linkCD->getFace(nodeD), "ndn:/P", 30);

	ndn::Face& appA = topo.addAppFace("A", nodeA)->getClientFace();
	ndn::Face& appD = topo.addAppFace("D", nodeD)->getClientFace();

	int nNacksA = 0, nNacksD = 0;
	appA.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksA]{ ++nNacksA; }), bind([]{}));
	appD.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksD]{ ++nNacksD; }), bind([]{}));
	this->advanceClocks(time::milliseconds(1), time::milliseconds(5));
	appA.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksA]{ ++nNacksA; }), bind([]{}));
	appD.expressInterest(Interest("/P/1"), bind([]{}), bind([&nNacksD]{ ++nNacksD; }), bind([]{}));
	this->advanceClocks(time::milliseconds(1), time::milliseconds(100));

	// As long as at least one Nack arrives at each client, strategy behavior is correct.
	// Whether both Interests are Nacked is a client face behavior, not strategy behavior.
	BOOST_CHECK_GT(nNacksA, 0);
	BOOST_CHECK_GT(nNacksD, 0);
	}

	template<lp::NackReason X, lp::NackReason Y, lp::NackReason R>
	struct NackReasonCombination
	{
	lp::NackReason
	getX() const
	{
	return X;
	}

	lp::NackReason
	getY() const
	{
	return Y;
	}

	lp::NackReason
	getExpectedResult() const
	{
	return R;
	}
	};

	typedef boost::mpl::vector<
	NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
	NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::DUPLICATE, lp::NackReason::CONGESTION>,
	NackReasonCombination<lp::NackReason::CONGESTION, lp::NackReason::NO_ROUTE, lp::NackReason::CONGESTION>,
	NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
	NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE>,
	NackReasonCombination<lp::NackReason::DUPLICATE, lp::NackReason::NO_ROUTE, lp::NackReason::DUPLICATE>,
	NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::CONGESTION, lp::NackReason::CONGESTION>,
	NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::DUPLICATE, lp::NackReason::DUPLICATE>,
	NackReasonCombination<lp::NackReason::NO_ROUTE, lp::NackReason::NO_ROUTE, lp::NackReason::NO_ROUTE>
	> NackReasonCombinations;

	BOOST_AUTO_TEST_CASE_TEMPLATE(CombineReasons, Combination, NackReasonCombinations)
	{
	Combination combination;

	fib::Entry& fibEntry = *fib.insert(Name()).first;
	fibEntry.addNextHop(*face3, 10);
	fibEntry.addNextHop(*face4, 20);
	fibEntry.addNextHop(*face5, 30);

	shared_ptr<Interest> interest1 = makeInterest("/F6sEwB24I", 282);
	shared_ptr<pit::Entry> pitEntry = pit.insert(*interest1).first;
	pitEntry->insertOrUpdateInRecord(face1, interest1);
	pitEntry->insertOrUpdateOutRecord(face3, interest1);
	pitEntry->insertOrUpdateOutRecord(face4, interest1);

	lp::Nack nack3 = makeNack("/F6sEwB24I", 282, combination.getX());
	pitEntry->getOutRecord(*face3)->setIncomingNack(nack3);
	strategy.afterReceiveNack(*face3, nack3, pitEntry);

	BOOST_CHECK_EQUAL(strategy.sendNackHistory.size(), 0);

	lp::Nack nack4 = makeNack("/F6sEwB24I", 282, combination.getY());
	pitEntry->getOutRecord(*face4)->setIncomingNack(nack4);
	strategy.afterReceiveNack(*face4, nack4, pitEntry);

	BOOST_REQUIRE_EQUAL(strategy.sendNackHistory.size(), 1);
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].pitInterest, pitEntry->getInterest());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].outFaceId, face1->getId());
	BOOST_CHECK_EQUAL(strategy.sendNackHistory[0].header.getReason(), combination.getExpectedResult());
	}

	BOOST_AUTO_TEST_SUITE_END() // IncomingNack

	BOOST_AUTO_TEST_SUITE_END() // TestBestRouteStrategy2
	BOOST_AUTO_TEST_SUITE_END() // Fw

	} // namespace tests
	} // namespace fw
	} // namespace nfd