// Copyright 2024 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/moqt/moqt_relay_track_publisher.h"

#include <cstdint>
#include <memory>
#include <optional>
#include <string>

#include "absl/strings/string_view.h"
#include "quiche/quic/core/quic_time.h"
#include "quiche/quic/moqt/moqt_error.h"
#include "quiche/quic/moqt/moqt_key_value_pair.h"
#include "quiche/quic/moqt/moqt_names.h"
#include "quiche/quic/moqt/moqt_object.h"
#include "quiche/quic/moqt/moqt_priority.h"
#include "quiche/quic/moqt/moqt_publisher.h"
#include "quiche/quic/moqt/moqt_session_interface.h"
#include "quiche/quic/moqt/moqt_types.h"
#include "quiche/quic/moqt/test_tools/mock_moqt_session.h"
#include "quiche/common/platform/api/quiche_expect_bug.h"
#include "quiche/common/platform/api/quiche_test.h"
#include "quiche/web_transport/web_transport.h"

namespace moqt::test {

namespace {

using ::testing::Optional;

const FullTrackName kTrackName = {"test", "track"};

class MockMoqtObjectListener : public MoqtObjectListener {
 public:
  MOCK_METHOD(void, OnSubscribeAccepted, (), (override));
  MOCK_METHOD(void, OnSubscribeRejected, (MoqtRequestErrorInfo reason),
              (override));
  MOCK_METHOD(void, OnNewObjectAvailable,
              (Location sequence, std::optional<uint64_t> subgroup,
               MoqtPriority publisher_priority),
              (override));
  MOCK_METHOD(void, OnNewFinAvailable,
              (Location final_object_in_subgroup, uint64_t subgroup_id),
              (override));
  MOCK_METHOD(void, OnSubgroupAbandoned,
              (uint64_t group, uint64_t subgroup,
               webtransport::StreamErrorCode error_code),
              (override));
  MOCK_METHOD(void, OnGroupAbandoned, (uint64_t group_id), (override));
  MOCK_METHOD(void, OnTrackPublisherGone, (), (override));
};

class MoqtRelayTrackPublisherTest : public quiche::test::QuicheTest {
 public:
  MoqtRelayTrackPublisherTest()
      : session_(std::make_unique<MockMoqtSession>()),
        publisher_(
            kTrackName, session_->GetWeakPtr(),
            [this]() { track_deleted_ = true; }, std::nullopt) {}

  void SubscribeAndOk() {
    EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
    publisher_.AddObjectListener(&listener_);
    EXPECT_CALL(listener_, OnSubscribeAccepted);
    MessageParameters parameters;
    parameters.largest_object = kLargestLocation;
    parameters.expires = quic::QuicTimeDelta::FromSeconds(30);
    publisher_.OnReply(kTrackName,
                       SubscribeOkData{parameters, TrackExtensions()});
  }

  void ObjectArrives(Location location, uint64_t subgroup,
                     MoqtObjectStatus status, absl::string_view payload,
                     bool fin_after_this = false) {
    EXPECT_CALL(listener_,
                OnNewObjectAvailable(location, Optional(subgroup), 128));
    if (fin_after_this || status == MoqtObjectStatus::kEndOfTrack ||
        status == MoqtObjectStatus::kEndOfGroup) {
      EXPECT_CALL(listener_, OnNewFinAvailable(location, subgroup));
    }
    publisher_.OnObjectFragment(
        kTrackName,
        PublishedObjectMetadata{location, subgroup, "", status, 128,
                                location.object == 0, payload.length()},
        payload, /*offset=*/0);
    std::optional<PublishedObject> object =
        publisher_.GetCachedObject(location.group, subgroup, location.object);
    ASSERT_TRUE(object.has_value());
    if (object.has_value()) {
      EXPECT_EQ(object->metadata.location, location);
      EXPECT_EQ(object->metadata.subgroup, subgroup);
      EXPECT_EQ(object->metadata.status, status);
      EXPECT_EQ(object->metadata.publisher_priority, 128);
      std::string full_payload;
      for (const auto& slice : object->payload) {
        full_payload += slice.AsStringView();
      }
      EXPECT_EQ(full_payload, payload);
      EXPECT_EQ(object->fin_after_this, fin_after_this);
    }
  }

  const Location kLargestLocation = Location(3, 2);

  bool track_deleted_ = false;
  std::unique_ptr<MockMoqtSession> session_;
  MockMoqtObjectListener listener_;
  MoqtRelayTrackPublisher publisher_;
};

TEST_F(MoqtRelayTrackPublisherTest, Queries) {
  EXPECT_EQ(publisher_.GetTrackName(), kTrackName);
  EXPECT_EQ(publisher_.largest_location(), std::nullopt);
  EXPECT_EQ(publisher_.expiration(), std::nullopt);

  SubscribeAndOk();
  EXPECT_EQ(publisher_.largest_location(), kLargestLocation);
  EXPECT_TRUE(publisher_.expiration().has_value() &&
              *publisher_.expiration() <= quic::QuicTimeDelta::FromSeconds(30));
}

TEST_F(MoqtRelayTrackPublisherTest, FiniteExpiration) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  EXPECT_CALL(listener_, OnSubscribeAccepted);
  MessageParameters parameters;
  parameters.largest_object = kLargestLocation;
  parameters.expires = quic::QuicTimeDelta::FromSeconds(30);
  publisher_.OnReply(kTrackName,
                     SubscribeOkData{parameters, TrackExtensions()});
  EXPECT_LT(publisher_.expiration(), quic::QuicTimeDelta::FromSeconds(31));
}

// TODO(martinduke): Write a test for track expiration. It will require
// altering private members in publisher_.

TEST_F(MoqtRelayTrackPublisherTest, SubscribeLifeCycle) {
  SubscribeAndOk();
  uint64_t subgroup = 0;
  Location last_location(3, 6);
  std::optional<PublishedObject> object;
  for (Location location = kLargestLocation.Next(); location < last_location;
       location = location.Next()) {
    ObjectArrives(location, subgroup, MoqtObjectStatus::kNormal, "object");
    // Two objects per subgroup.
    if (location.object % 2 == 0) {
      ++subgroup;
    }
  }
  // End of Group object.
  ObjectArrives(last_location, subgroup, MoqtObjectStatus::kEndOfGroup, "",
                true);
  // End of Track object.
  last_location = Location(4, 0);
  subgroup = 0;
  ObjectArrives(last_location, subgroup, MoqtObjectStatus::kEndOfTrack, "",
                true);

  // TODO(martinduke): Gracefully close the subscription.
}

TEST_F(MoqtRelayTrackPublisherTest, GroupAbandoned) {
  SubscribeAndOk();
  for (uint64_t group = kLargestLocation.group + 1;
       group < kLargestLocation.group + 5; ++group) {
    if (group - kLargestLocation.group > 3) {
      EXPECT_CALL(listener_, OnGroupAbandoned(group - 3));
    }
    EXPECT_CALL(listener_,
                OnNewObjectAvailable(Location(group, 0), Optional(0), 128));
    publisher_.OnObjectFragment(
        kTrackName,
        PublishedObjectMetadata{Location(group, 0), 0, "",
                                MoqtObjectStatus::kEndOfGroup, 128, true, 0},
        "", /*offset=*/0);
  }
}

TEST_F(MoqtRelayTrackPublisherTest, BeyondEndOfTrack) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  ObjectArrives(location, 0, MoqtObjectStatus::kEndOfTrack, "", true);
  EXPECT_FALSE(track_deleted_);
  location = location.Next();
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "", MoqtObjectStatus::kNormal, 128,
                              location.object == 0, 6},
      "object", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, EndOfTrackTooEarly) {
  SubscribeAndOk();
  Location first_location = kLargestLocation.Next();
  Location second_location = first_location.Next();
  ObjectArrives(second_location, 0, MoqtObjectStatus::kNormal, "object", false);
  EXPECT_FALSE(track_deleted_);
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{first_location, 0, "",
                              MoqtObjectStatus::kEndOfTrack, 128,
                              first_location.object == 0, 0},
      "", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, BeyondEndOfGroup) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  ObjectArrives(location, 0, MoqtObjectStatus::kEndOfGroup, "", true);
  EXPECT_FALSE(track_deleted_);
  location = location.Next();
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 1, "", MoqtObjectStatus::kEndOfGroup,
                              128, location.object == 0, 6},
      "object", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, EndOfGroupTooEarly) {
  SubscribeAndOk();
  Location first_location = kLargestLocation.Next();
  Location second_location = first_location.Next();
  ObjectArrives(second_location, 0, MoqtObjectStatus::kNormal, "object", false);
  EXPECT_FALSE(track_deleted_);
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{first_location, 1, "",
                              MoqtObjectStatus::kEndOfGroup, 128,
                              first_location.object == 0, 0},
      "", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, PriorityChange) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  ObjectArrives(location, 0, MoqtObjectStatus::kNormal, "object", false);
  EXPECT_FALSE(track_deleted_);
  location = location.Next();
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "", MoqtObjectStatus::kNormal, 200,
                              location.object == 0, 6},
      "object", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

// TODO(martinduke): Enable this test once the class supports explicit FIN.
#if 0
TEST_F(MoqtRelayTrackPublisherTest, ObjectAfterFin) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  ObjectArrives(location, 0, MoqtObjectStatus::kNormal, "object", true);
  EXPECT_FALSE(track_deleted_);
  location = location.Next();
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "", MoqtObjectStatus::kNormal, 128,
                              location.object == 0, 6},
      "object", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}
#endif

TEST_F(MoqtRelayTrackPublisherTest, ObjectOutOfOrder) {
  SubscribeAndOk();
  Location first_location = kLargestLocation.Next();
  Location second_location = first_location.Next();
  ObjectArrives(second_location, 0, MoqtObjectStatus::kNormal, "object", false);
  EXPECT_FALSE(track_deleted_);
  EXPECT_CALL(listener_, OnNewObjectAvailable).Times(0);
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{first_location, 0, "", MoqtObjectStatus::kNormal,
                              128, first_location.object == 0, 6},
      "object", /*offset=*/0);
  // Object is simply ignored; track is not malformed.
  EXPECT_FALSE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, CacheMisses) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  ObjectArrives(location, 0, MoqtObjectStatus::kNormal, "object", false);
  // Nonexistent group.
  EXPECT_FALSE(
      publisher_.GetCachedObject(location.group + 1, 0, location.object)
          .has_value());
  // Nonexistent subgroup.
  EXPECT_FALSE(publisher_.GetCachedObject(location.group, 1, location.object)
                   .has_value());
  // Object ID too high.
  EXPECT_FALSE(
      publisher_.GetCachedObject(location.group, 0, location.object + 1)
          .has_value());
}

TEST_F(MoqtRelayTrackPublisherTest, SubscribeRejected) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  EXPECT_CALL(listener_, OnSubscribeRejected).WillOnce([this] {
    publisher_.RemoveObjectListener(&listener_);
  });
  publisher_.OnReply(kTrackName,
                     MoqtRequestErrorInfo{RequestErrorCode::kUnauthorized,
                                          std::nullopt, "Unauthorized"});
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, LastListenerGone) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  EXPECT_CALL(*session_, Unsubscribe(kTrackName));
  publisher_.RemoveObjectListener(&listener_);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, SessionDies) {
  session_.reset();
  EXPECT_CALL(listener_, OnSubscribeRejected);
  publisher_.AddObjectListener(&listener_);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, SecondListenerNoSubscribe) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  EXPECT_CALL(*session_, Subscribe).Times(0);
  EXPECT_CALL(listener_, OnSubscribeAccepted).Times(0);
  MockMoqtObjectListener listener2;
  publisher_.AddObjectListener(&listener2);
  EXPECT_CALL(listener_, OnSubscribeAccepted);
  EXPECT_CALL(listener2, OnSubscribeAccepted);
  MessageParameters parameters;
  parameters.largest_object = kLargestLocation;
  publisher_.OnReply(kTrackName,
                     SubscribeOkData{parameters, TrackExtensions()});
}

TEST_F(MoqtRelayTrackPublisherTest, OnMalformedObject) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  publisher_.OnMalformedTrack(kTrackName);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, DuplicateObject) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  Location location = kLargestLocation.Next();
  EXPECT_CALL(listener_, OnNewObjectAvailable(location, Optional(0),
                                              /*publisher_priority=*/128));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal,
                              128, location.object == 0, 6},
      "object", /*offset=*/0);
  // Exact duplicate is ignored. It doesn't matter that the arrival time
  // changed.
  EXPECT_CALL(listener_, OnNewObjectAvailable).Times(0);
  EXPECT_CALL(listener_, OnTrackPublisherGone).Times(0);
  EXPECT_FALSE(track_deleted_);
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal,
                              128, location.object == 0, 6,
                              quic::QuicTime::Infinite()},
      "object", /*offset=*/0);
}

TEST_F(MoqtRelayTrackPublisherTest, DuplicateObjectChangedMetadata) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  Location location = kLargestLocation.Next();
  EXPECT_CALL(listener_, OnNewObjectAvailable(location, Optional(0),
                                              /*publisher_priority=*/128));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal,
                              128, location.object == 0, 6},
      "object", /*offset=*/0);
  // Priority change; malformed track.
  EXPECT_CALL(listener_, OnNewObjectAvailable).Times(0);
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal, 64,
                              location.object == 0, 6},
      "object", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, DuplicateObjectChangedPayload) {
  EXPECT_CALL(*session_, Subscribe).WillOnce(testing::Return(true));
  publisher_.AddObjectListener(&listener_);
  Location location = kLargestLocation.Next();
  EXPECT_CALL(listener_, OnNewObjectAvailable(location, Optional(0),
                                              /*publisher_priority=*/128));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal,
                              128, location.object == 0, 7},
      "payload", /*offset=*/0);
  // Payload change; malformed track.
  EXPECT_CALL(listener_, OnNewObjectAvailable).Times(0);
  EXPECT_CALL(listener_, OnTrackPublisherGone);
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, 0, "foo", MoqtObjectStatus::kNormal,
                              128, location.object == 0, 6},
      "foobar", /*offset=*/0);
  EXPECT_TRUE(track_deleted_);
}

TEST_F(MoqtRelayTrackPublisherTest, Fin) {
  SubscribeAndOk();

  // No stream to FIN.
  EXPECT_CALL(listener_, OnNewFinAvailable).Times(0);
  publisher_.OnStreamFin(kTrackName, DataStreamIndex{2, 0});

  ObjectArrives(Location(4, 0), 0, MoqtObjectStatus::kNormal, "object", false);
  std::optional<PublishedObject> object = publisher_.GetCachedObject(4, 0, 0);
  EXPECT_FALSE(object.has_value() && object->fin_after_this);

  EXPECT_CALL(listener_, OnNewFinAvailable(Location(4, 0), 0));
  publisher_.OnStreamFin(kTrackName, DataStreamIndex{4, 0});
  // Object now has fin_after_this set.
  object = publisher_.GetCachedObject(4, 0, 0);
  EXPECT_TRUE(object.has_value() && object->fin_after_this);
}

TEST_F(MoqtRelayTrackPublisherTest, Reset) {
  SubscribeAndOk();

  EXPECT_CALL(listener_, OnSubgroupAbandoned(2, 0, kResetCodeCancelled));
  publisher_.OnStreamReset(kTrackName, DataStreamIndex{2, 0});
}

TEST_F(MoqtRelayTrackPublisherTest, SecondSubscribeAfterOk) {
  SubscribeAndOk();
  EXPECT_CALL(*session_, Subscribe).Times(0);
  MockMoqtObjectListener listener2;
  EXPECT_CALL(listener2, OnSubscribeAccepted);
  publisher_.AddObjectListener(&listener2);
}

TEST_F(MoqtRelayTrackPublisherTest, DatagramPreference) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  EXPECT_CALL(listener_,
              OnNewObjectAvailable(location, testing::Eq(std::nullopt),
                                   /*publisher_priority=*/128));
  publisher_.OnObjectFragment(
      kTrackName,
      PublishedObjectMetadata{location, std::nullopt, "",
                              MoqtObjectStatus::kNormal, 128, std::nullopt, 6},
      "object", /*offset=*/0);
  std::optional<PublishedObject> object =
      publisher_.GetCachedObject(location.group, std::nullopt, 0);
  EXPECT_TRUE(object.has_value() && !object->metadata.subgroup.has_value());
}

TEST_F(MoqtRelayTrackPublisherTest, ObjectArrivalInFragments) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  uint64_t subgroup = 0;
  // Total size is 15 bytes.
  PublishedObjectMetadata metadata = {location, subgroup,
                                      "",       MoqtObjectStatus::kNormal,
                                      128,      location.object == 0,
                                      15};

  // Fragment 1 arrives.
  EXPECT_CALL(listener_,
              OnNewObjectAvailable(location, Optional(subgroup), 128));
  publisher_.OnObjectFragment(kTrackName, metadata, "frag1", 0);

  // Fragment 2 arrives.
  EXPECT_CALL(listener_,
              OnNewObjectAvailable(location, Optional(subgroup), 128));
  publisher_.OnObjectFragment(kTrackName, metadata, "frag2", 5);

  // Session retrieves the object with two fragments.
  std::optional<PublishedObject> object =
      publisher_.GetCachedObject(location.group, subgroup, location.object, 0);
  ASSERT_TRUE(object.has_value());
  std::string payload;
  for (const auto& slice : object->payload) {
    payload += std::string(slice.AsStringView());
  }
  EXPECT_EQ(payload, "frag1frag2");

  // Fragment 3 arrives.
  EXPECT_CALL(listener_,
              OnNewObjectAvailable(location, Optional(subgroup), 128));
  publisher_.OnObjectFragment(kTrackName, metadata, "frag3", 10);

  // Third fragment retrieved separately.
  object =
      publisher_.GetCachedObject(location.group, subgroup, location.object, 10);
  ASSERT_TRUE(object.has_value());
  payload.clear();
  for (const auto& slice : object->payload) {
    payload += std::string(slice.AsStringView());
  }
  EXPECT_EQ(payload, "frag3");
}

TEST_F(MoqtRelayTrackPublisherTest, IncompleteDatagram) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  PublishedObjectMetadata metadata = {
      location, std::nullopt, "", MoqtObjectStatus::kNormal,
      128,      std::nullopt, 10};
  // Fragment length mismatch.
  EXPECT_QUICHE_BUG(
      publisher_.OnObjectFragment(kTrackName, metadata, "short", 0),
      "Received a partial datagram.");
  // Non-zero offset for datagram.
  EXPECT_QUICHE_BUG(
      publisher_.OnObjectFragment(kTrackName, metadata, "payload10", 1),
      "Received a partial datagram.");
}

TEST_F(MoqtRelayTrackPublisherTest, AlreadyReceivedFragment) {
  SubscribeAndOk();
  Location location = kLargestLocation.Next();
  uint64_t subgroup = 0;
  // Total size is 15 bytes.
  PublishedObjectMetadata metadata = {location, subgroup,
                                      "",       MoqtObjectStatus::kNormal,
                                      128,      location.object == 0,
                                      15};

  // Fragment 1 arrives (first 10 bytes).
  EXPECT_CALL(listener_,
              OnNewObjectAvailable(location, Optional(subgroup), 128));
  publisher_.OnObjectFragment(kTrackName, metadata, "0123456789", 0);

  // Send a fragment that has already been fully received.
  // Partial overlap, matches earlier data. Append() will be called with
  // (0, "01234").
  // Since payload_received_ (10) > 0 + 5, Append() returns false.
  // OnObjectFragment should just return without notifying listeners.
  EXPECT_CALL(listener_, OnNewObjectAvailable).Times(0);
  publisher_.OnObjectFragment(kTrackName, metadata, "01234", 0);

  std::optional<PublishedObject> object =
      publisher_.GetCachedObject(location.group, subgroup, location.object, 0);
  ASSERT_TRUE(object.has_value());
  // Verify that only the first 10 bytes are cached.
  std::string payload;
  for (const auto& slice : object->payload) {
    payload += std::string(slice.AsStringView());
  }
  EXPECT_EQ(payload, "0123456789");
}

}  // namespace

}  // namespace moqt::test