transmission/tests/libtransmission/announcer-udp-test.cc

649 lines
25 KiB
C++

// This file Copyright (C) 2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <cstring> // for std::memcpy()
#include <deque>
#include <memory>
#include <vector>
#include <fmt/format.h>
#define LIBTRANSMISSION_ANNOUNCER_MODULE
#include "transmission.h"
#include "announcer.h"
#include "announcer-common.h"
#include "crypto-utils.h" // for tr_rand_obj()
#include "peer-mgr.h" // for tr_pex
#include "timer-ev.h"
#include "tr-buffer.h"
#include "test-fixtures.h"
using namespace std::literals;
class AnnouncerUdpTest : public ::testing::Test
{
private:
void SetUp() override
{
tr_net_init();
::testing::Test::SetUp();
tr_timeUpdate(time(nullptr));
}
protected:
class MockMediator final : public tr_announcer_udp::Mediator
{
public:
MockMediator()
: event_base_{ event_base_new(), event_base_free }
{
}
void sendto(void const* buf, size_t buflen, sockaddr const* sa, socklen_t salen) override
{
auto target = tr_address::from_sockaddr(sa);
ASSERT_TRUE(target);
sent_.emplace_back(static_cast<char const*>(buf), buflen, sa, salen);
}
[[nodiscard]] auto* eventBase()
{
return event_base_.get();
}
[[nodiscard]] std::optional<tr_address> announceIP() const override
{
return {};
}
struct Sent
{
Sent() = default;
Sent(char const* buf, size_t buflen, sockaddr const* sa, socklen_t salen)
: sslen_{ salen }
{
buf_.insert(std::end(buf_), buf, buf + buflen);
std::memcpy(&ss_, sa, salen);
}
std::vector<char> buf_;
sockaddr_storage ss_ = {};
socklen_t sslen_ = {};
};
std::deque<Sent> sent_;
std::unique_ptr<event_base, void (*)(event_base*)> const event_base_;
};
static void expectEqual(tr_scrape_response const& expected, tr_scrape_response const& actual)
{
EXPECT_EQ(expected.did_connect, actual.did_connect);
EXPECT_EQ(expected.did_timeout, actual.did_timeout);
EXPECT_EQ(expected.errmsg, actual.errmsg);
EXPECT_EQ(expected.min_request_interval, actual.min_request_interval);
EXPECT_EQ(expected.scrape_url, actual.scrape_url);
EXPECT_EQ(expected.row_count, actual.row_count);
for (int i = 0; i < std::min(expected.row_count, actual.row_count); ++i)
{
EXPECT_EQ(expected.rows[i].info_hash, actual.rows[i].info_hash);
EXPECT_EQ(expected.rows[i].seeders, actual.rows[i].seeders);
EXPECT_EQ(expected.rows[i].leechers, actual.rows[i].leechers);
EXPECT_EQ(expected.rows[i].downloads, actual.rows[i].downloads);
EXPECT_EQ(expected.rows[i].downloaders, actual.rows[i].downloaders);
}
}
static void expectEqual(tr_scrape_request const& expected, std::vector<tr_sha1_digest_t> const& actual)
{
EXPECT_EQ(expected.info_hash_count, std::size(actual));
for (size_t i = 0; i < std::min(static_cast<size_t>(expected.info_hash_count), std::size(actual)); ++i)
{
EXPECT_EQ(expected.info_hash[i], actual[i]);
}
}
[[nodiscard]] static uint32_t parseConnectionRequest(libtransmission::Buffer& buf)
{
EXPECT_EQ(ProtocolId, buf.toUint64());
EXPECT_EQ(ConnectAction, buf.toUint32());
return buf.toUint32();
}
[[nodiscard]] static auto buildScrapeRequestFromResponse(tr_scrape_response const& response)
{
auto request = tr_scrape_request{};
request.scrape_url = response.scrape_url;
request.info_hash_count = response.row_count;
for (int i = 0; i < request.info_hash_count; ++i)
{
request.info_hash[i] = response.rows[i].info_hash;
}
return request;
}
[[nodiscard]] static auto buildSimpleScrapeRequestAndResponse()
{
auto response = tr_scrape_response{};
response.did_connect = true;
response.did_timeout = false;
response.row_count = 1;
response.rows[0].info_hash = tr_rand_obj<tr_sha1_digest_t>();
response.rows[0].seeders = 1;
response.rows[0].leechers = 2;
response.rows[0].downloads = 3;
response.rows[0].downloaders = 0;
response.scrape_url = DefaultScrapeUrl;
response.min_request_interval = 0;
return std::make_pair(buildScrapeRequestFromResponse(response), response);
}
[[nodiscard]] static auto parseScrapeRequest(libtransmission::Buffer& buf, uint64_t expected_connection_id)
{
EXPECT_EQ(expected_connection_id, buf.toUint64());
EXPECT_EQ(ScrapeAction, buf.toUint32());
auto const transaction_id = buf.toUint32();
auto info_hashes = std::vector<tr_sha1_digest_t>{};
while (!std::empty(buf))
{
auto tmp = tr_sha1_digest_t{};
buf.toBuf(std::data(tmp), std::size(tmp));
info_hashes.emplace_back(tmp);
}
return std::make_pair(transaction_id, info_hashes);
}
[[nodiscard]] static auto waitForAnnouncerToSendMessage(MockMediator& mediator)
{
libtransmission::test::waitFor(mediator.eventBase(), [&mediator]() { return !std::empty(mediator.sent_); });
auto buf = libtransmission::Buffer(mediator.sent_.back().buf_);
mediator.sent_.pop_back();
return buf;
}
[[nodiscard]] static bool sendError(tr_announcer_udp& announcer, uint32_t transaction_id, std::string_view errmsg)
{
auto buf = libtransmission::Buffer{};
buf.addUint32(ErrorAction);
buf.addUint32(transaction_id);
buf.add(errmsg);
auto const response_size = std::size(buf);
auto arr = std::array<uint8_t, 256>{};
buf.toBuf(std::data(arr), response_size);
return announcer.handleMessage(std::data(arr), response_size);
}
[[nodiscard]] static auto sendConnectionResponse(tr_announcer_udp& announcer, uint32_t transaction_id)
{
auto const connection_id = tr_rand_obj<uint64_t>();
auto buf = libtransmission::Buffer{};
buf.addUint32(ConnectAction);
buf.addUint32(transaction_id);
buf.addUint64(connection_id);
auto arr = std::array<uint8_t, 128>{};
auto response_size = std::size(buf);
buf.toBuf(std::data(arr), response_size);
EXPECT_TRUE(announcer.handleMessage(std::data(arr), response_size));
return connection_id;
}
struct UdpAnnounceReq
{
uint64_t connection_id = 0;
uint32_t action = 0; // 1: announce
uint32_t transaction_id = 0;
tr_sha1_digest_t info_hash = {};
tr_peer_id_t peer_id = {};
uint64_t downloaded = 0;
uint64_t left = 0;
uint64_t uploaded = 0;
uint32_t event = 0; // 0: none; 1: completed; 2: started; 3: stopped
uint32_t ip_address = 0;
uint32_t key;
uint32_t num_want = static_cast<uint32_t>(-1); // default
uint16_t port;
};
static void expectEqual(tr_announce_request const& expected, UdpAnnounceReq const& actual)
{
EXPECT_EQ(AnnounceAction, actual.action);
EXPECT_EQ(expected.info_hash, actual.info_hash);
EXPECT_EQ(expected.peer_id, actual.peer_id);
EXPECT_EQ(expected.down, actual.downloaded);
EXPECT_EQ(expected.leftUntilComplete, actual.left);
EXPECT_EQ(expected.up, actual.uploaded);
// EXPECT_EQ(foo, actual.event); ; // 0: none; 1: completed; 2: started; 3: stopped // FIXME
// EXPECT_EQ(foo, actual.ip_address); // FIXME
EXPECT_EQ(expected.key, static_cast<int>(actual.key));
EXPECT_EQ(expected.numwant, static_cast<int>(actual.num_want));
EXPECT_EQ(expected.port.host(), actual.port);
}
static void expectEqual(tr_announce_response const& expected, tr_announce_response const& actual)
{
EXPECT_EQ(actual.info_hash, expected.info_hash);
EXPECT_EQ(actual.did_connect, expected.did_connect);
EXPECT_EQ(actual.did_timeout, expected.did_timeout);
EXPECT_EQ(actual.interval, expected.interval);
EXPECT_EQ(actual.min_interval, expected.min_interval);
EXPECT_EQ(actual.seeders, expected.seeders);
EXPECT_EQ(actual.leechers, expected.leechers);
EXPECT_EQ(actual.downloads, expected.downloads);
EXPECT_EQ(actual.pex, expected.pex);
EXPECT_EQ(actual.pex6, expected.pex6);
EXPECT_EQ(actual.errmsg, expected.errmsg);
EXPECT_EQ(actual.warning, expected.warning);
EXPECT_EQ(actual.tracker_id, expected.tracker_id);
EXPECT_EQ(actual.external_ip, expected.external_ip);
}
[[nodiscard]] static auto parseAnnounceRequest(libtransmission::Buffer& buf, uint64_t connection_id)
{
auto req = UdpAnnounceReq{};
req.connection_id = buf.toUint64();
req.action = buf.toUint32();
req.transaction_id = buf.toUint32();
buf.toBuf(std::data(req.info_hash), std::size(req.info_hash));
buf.toBuf(std::data(req.peer_id), std::size(req.peer_id));
req.downloaded = buf.toUint64();
req.left = buf.toUint64();
req.uploaded = buf.toUint64();
req.event = buf.toUint32();
req.ip_address = buf.toUint32();
req.key = buf.toUint32();
req.num_want = buf.toUint32();
req.port = buf.toUint16();
EXPECT_EQ(AnnounceAction, req.action);
EXPECT_EQ(connection_id, req.connection_id);
return req;
}
// emulate the upkeep timer that tr_announcer runs in production
static auto createUpkeepTimer(MockMediator& mediator, std::unique_ptr<tr_announcer_udp>& announcer)
{
auto timer_maker = libtransmission::EvTimerMaker{ mediator.eventBase() };
auto timer = timer_maker.create();
timer->setCallback([&announcer]() { announcer->upkeep(); });
timer->startRepeating(200ms);
return timer;
}
// https://www.bittorrent.org/beps/bep_0015.html
static auto constexpr ProtocolId = uint64_t{ 0x41727101980ULL };
static auto constexpr ConnectAction = uint32_t{ 0 };
static auto constexpr AnnounceAction = uint32_t{ 1 };
static auto constexpr ScrapeAction = uint32_t{ 2 };
static auto constexpr ErrorAction = uint32_t{ 3 };
static auto constexpr DefaultScrapeUrl = "https://127.0.0.1/scrape"sv;
};
TEST_F(AnnouncerUdpTest, canInstantiate)
{
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
EXPECT_TRUE(announcer);
}
TEST_F(AnnouncerUdpTest, canScrape)
{
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
// tell announcer to scrape
auto [request, expected_response] = buildSimpleScrapeRequestAndResponse();
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
auto sent = waitForAnnouncerToSendMessage(mediator);
auto connect_transaction_id = parseConnectionRequest(sent);
// Have the tracker respond to the request
auto const connection_id = sendConnectionResponse(*announcer, connect_transaction_id);
// The announcer should have sent a UDP scrape request.
// Inspect that request for validity.
sent = waitForAnnouncerToSendMessage(mediator);
auto [scrape_transaction_id, info_hashes] = parseScrapeRequest(sent, connection_id);
expectEqual(request, info_hashes);
// Have the tracker respond to the request
auto buf = libtransmission::Buffer{};
buf.addUint32(ScrapeAction);
buf.addUint32(scrape_transaction_id);
buf.addUint32(expected_response.rows[0].seeders);
buf.addUint32(expected_response.rows[0].downloads);
buf.addUint32(expected_response.rows[0].leechers);
auto response_size = std::size(buf);
auto arr = std::array<uint8_t, 256>{};
buf.toBuf(std::data(arr), response_size);
EXPECT_TRUE(announcer->handleMessage(std::data(arr), response_size));
// confirm that announcer processed the response
EXPECT_TRUE(response);
expectEqual(expected_response, *response);
// Now scrape again.
// Since the timestamp hasn't changed, the connection should be good
// and announcer-udp should skip the `connect` step, going straight to the scrape.
response.reset();
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
sent = waitForAnnouncerToSendMessage(mediator);
std::tie(scrape_transaction_id, info_hashes) = parseScrapeRequest(sent, connection_id);
expectEqual(request, info_hashes);
}
TEST_F(AnnouncerUdpTest, canDestructCleanlyEvenWhenBusy)
{
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
// tell announcer to scrape
auto [request, expected_response] = buildSimpleScrapeRequestAndResponse();
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
auto sent = waitForAnnouncerToSendMessage(mediator);
auto const connect_transaction_id = parseConnectionRequest(sent);
EXPECT_NE(0U, connect_transaction_id);
// now just end the test before responding to the request.
// the announcer and mediator will go out-of-scope & be destroyed.
}
TEST_F(AnnouncerUdpTest, canMultiScrape)
{
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
auto expected_response = tr_scrape_response{};
expected_response.did_connect = true;
expected_response.did_timeout = false;
expected_response.row_count = 2;
expected_response.rows[0] = { tr_rand_obj<tr_sha1_digest_t>(), 1, 2, 3, 0 };
expected_response.rows[1] = { tr_rand_obj<tr_sha1_digest_t>(), 4, 5, 6, 0 };
expected_response.scrape_url = DefaultScrapeUrl;
expected_response.min_request_interval = 0;
auto request = buildScrapeRequestFromResponse(expected_response);
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// Announcer will request a connection. Verify and grant the request
auto sent = waitForAnnouncerToSendMessage(mediator);
auto connect_transaction_id = parseConnectionRequest(sent);
auto const connection_id = sendConnectionResponse(*announcer, connect_transaction_id);
// The announcer should have sent a UDP scrape request.
// Inspect that request for validity.
sent = waitForAnnouncerToSendMessage(mediator);
auto [scrape_transaction_id, info_hashes] = parseScrapeRequest(sent, connection_id);
expectEqual(request, info_hashes);
// Have the tracker respond to the request
auto buf = libtransmission::Buffer{};
buf.addUint32(ScrapeAction);
buf.addUint32(scrape_transaction_id);
for (size_t i = 0; i < expected_response.row_count; ++i)
{
buf.addUint32(expected_response.rows[i].seeders);
buf.addUint32(expected_response.rows[i].downloads);
buf.addUint32(expected_response.rows[i].leechers);
}
auto response_size = std::size(buf);
auto arr = std::array<uint8_t, 256>{};
buf.toBuf(std::data(arr), response_size);
EXPECT_TRUE(announcer->handleMessage(std::data(arr), response_size));
// Confirm that announcer processed the response
EXPECT_TRUE(response);
expectEqual(expected_response, *response);
}
TEST_F(AnnouncerUdpTest, canHandleScrapeError)
{
// build the expected reponse
auto expected_response = tr_scrape_response{};
expected_response.did_connect = true;
expected_response.did_timeout = false;
expected_response.row_count = 1;
expected_response.rows[0].info_hash = tr_rand_obj<tr_sha1_digest_t>();
expected_response.rows[0].seeders = -1;
expected_response.rows[0].leechers = -1;
expected_response.rows[0].downloads = -1;
expected_response.rows[0].downloaders = 0;
expected_response.scrape_url = DefaultScrapeUrl;
expected_response.min_request_interval = 0;
expected_response.errmsg = "Unrecognized info-hash";
// build the request
auto request = buildScrapeRequestFromResponse(expected_response);
// build the announcer
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
// tell announcer to scrape
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
auto sent = waitForAnnouncerToSendMessage(mediator);
auto connect_transaction_id = parseConnectionRequest(sent);
// Have the tracker respond to the request
auto const connection_id = sendConnectionResponse(*announcer, connect_transaction_id);
// The announcer should have sent a UDP scrape request.
// Inspect that request for validity.
sent = waitForAnnouncerToSendMessage(mediator);
auto const [scrape_transaction_id, info_hashes] = parseScrapeRequest(sent, connection_id);
// Have the tracker respond to the request with an "unable to scrape" error
EXPECT_TRUE(sendError(*announcer, scrape_transaction_id, expected_response.errmsg));
// confirm that announcer processed the response
EXPECT_TRUE(response);
expectEqual(expected_response, *response);
}
TEST_F(AnnouncerUdpTest, canHandleConnectError)
{
// build the response we'd expect for a connect failure
auto expected_response = tr_scrape_response{};
expected_response.did_connect = true;
expected_response.did_timeout = false;
expected_response.row_count = 1;
expected_response.rows[0].info_hash = tr_rand_obj<tr_sha1_digest_t>();
expected_response.rows[0].seeders = -1; // -1 here & on next lines means error
expected_response.rows[0].leechers = -1;
expected_response.rows[0].downloads = -1;
expected_response.rows[0].downloaders = 0;
expected_response.scrape_url = DefaultScrapeUrl;
expected_response.min_request_interval = 0;
expected_response.errmsg = "Unable to Connect";
// build the announcer
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
// tell the announcer to scrape
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(
buildScrapeRequestFromResponse(expected_response),
[&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
auto sent = waitForAnnouncerToSendMessage(mediator);
auto transaction_id = parseConnectionRequest(sent);
// Have the tracker respond to the request with an "unable to connect" error
EXPECT_TRUE(sendError(*announcer, transaction_id, expected_response.errmsg));
// Confirm that announcer processed the response
EXPECT_TRUE(response);
expectEqual(expected_response, *response);
}
TEST_F(AnnouncerUdpTest, handleMessageReturnsFalseOnInvalidMessage)
{
// build a simple scrape request
auto request = tr_scrape_request{};
request.scrape_url = DefaultScrapeUrl;
request.info_hash_count = 1;
request.info_hash[0] = tr_rand_obj<tr_sha1_digest_t>();
// build the announcer
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
// tell the announcer to scrape
auto response = std::optional<tr_scrape_response>{};
announcer->scrape(request, [&response](tr_scrape_response const& resp) { response = resp; });
// The announcer should have sent a UDP connection request.
// Inspect that request for validity.
auto sent = waitForAnnouncerToSendMessage(mediator);
auto transaction_id = parseConnectionRequest(sent);
// send a connection response but with an *invalid* transaction id
auto buf = libtransmission::Buffer{};
buf.addUint32(ConnectAction);
buf.addUint32(transaction_id + 1);
buf.addUint64(tr_rand_obj<uint64_t>());
auto response_size = std::size(buf);
auto arr = std::array<uint8_t, 256>{};
buf.toBuf(std::data(arr), response_size);
EXPECT_FALSE(announcer->handleMessage(std::data(arr), response_size));
// send a connection response but with an *invalid* action
buf.clear();
buf.addUint32(ScrapeAction);
buf.addUint32(transaction_id);
buf.addUint64(tr_rand_obj<uint64_t>());
response_size = std::size(buf);
buf.toBuf(std::data(arr), response_size);
EXPECT_FALSE(announcer->handleMessage(std::data(arr), response_size));
// but after discarding invalid messages,
// a valid connection response should still work
auto const connection_id = sendConnectionResponse(*announcer, transaction_id);
EXPECT_NE(0, connection_id);
}
TEST_F(AnnouncerUdpTest, canAnnounce)
{
static auto constexpr Interval = uint32_t{ 3600 };
static auto constexpr Leechers = uint32_t{ 10 };
static auto constexpr Seeders = uint32_t{ 20 };
auto const addresses = std::array<std::pair<tr_address, tr_port>, 3>{
std::make_pair(tr_address::from_string("10.10.10.5").value_or(tr_address{}), tr_port::fromHost(128)),
std::make_pair(tr_address::from_string("192.168.1.2").value_or(tr_address{}), tr_port::fromHost(2021)),
std::make_pair(tr_address::from_string("192.168.1.3").value_or(tr_address{}), tr_port::fromHost(2022)),
};
auto request = tr_announce_request{};
request.event = TR_ANNOUNCE_EVENT_STARTED;
request.port = tr_port::fromHost(80);
request.key = 0xCAFE;
request.numwant = 20;
request.up = 1;
request.down = 2;
request.corrupt = 3;
request.leftUntilComplete = 100;
request.announce_url = "https://127.0.0.1/announce";
request.tracker_id = "fnord";
request.peer_id = tr_peerIdInit();
request.info_hash = tr_rand_obj<tr_sha1_digest_t>();
auto expected_response = tr_announce_response{};
expected_response.info_hash = request.info_hash;
expected_response.did_connect = true;
expected_response.did_timeout = false;
expected_response.interval = Interval;
expected_response.min_interval = 0; // not specified in UDP announce
expected_response.seeders = Seeders;
expected_response.leechers = Leechers;
expected_response.downloads = -1; // not specified in UDP anounce
expected_response.pex = std::vector<tr_pex>{ tr_pex{ addresses[0].first, addresses[0].second },
tr_pex{ addresses[1].first, addresses[1].second },
tr_pex{ addresses[2].first, addresses[2].second } };
expected_response.pex6 = {};
expected_response.errmsg = {};
expected_response.warning = {};
expected_response.tracker_id = {}; // not specified in UDP announce
expected_response.external_ip = {};
// build the announcer
auto mediator = MockMediator{};
auto announcer = tr_announcer_udp::create(mediator);
auto upkeep_timer = createUpkeepTimer(mediator, announcer);
auto response = std::optional<tr_announce_response>{};
announcer->announce(request, [&response](tr_announce_response const& resp) { response = resp; });
// Announcer will request a connection. Verify and grant the request
auto sent = waitForAnnouncerToSendMessage(mediator);
auto connect_transaction_id = parseConnectionRequest(sent);
auto const connection_id = sendConnectionResponse(*announcer, connect_transaction_id);
// The announcer should have sent a UDP announce request.
// Inspect that request for validity.
sent = waitForAnnouncerToSendMessage(mediator);
auto udp_ann_req = parseAnnounceRequest(sent, connection_id);
expectEqual(request, udp_ann_req);
// Have the tracker respond to the request
auto buf = libtransmission::Buffer{};
buf.addUint32(AnnounceAction);
buf.addUint32(udp_ann_req.transaction_id);
buf.addUint32(expected_response.interval);
buf.addUint32(expected_response.leechers);
buf.addUint32(expected_response.seeders);
for (auto const& [addr, port] : addresses)
{
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-union-access)
buf.add(&addr.addr.addr4.s_addr, sizeof(addr.addr.addr4.s_addr));
buf.addUint16(port.host());
}
auto response_size = std::size(buf);
auto arr = std::array<uint8_t, 512>{};
buf.toBuf(std::data(arr), response_size);
EXPECT_TRUE(announcer->handleMessage(std::data(arr), response_size));
// Confirm that announcer processed the response
EXPECT_TRUE(response);
expectEqual(expected_response, *response);
}