Add FlexFEC header formatters. (pt. 5)

webrtc/modules/rtp_rtcp/source/flexfec_header_reader_writer_unittest.cc

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <string.h>
+
+#include <memory>
+#include <utility>
+
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/base/basictypes.h"
+#include "webrtc/base/checks.h"
+#include "webrtc/base/random.h"
+#include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+#include "webrtc/modules/rtp_rtcp/source/flexfec_header_reader_writer.h"
+#include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
+#include "webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h"
+
+namespace webrtc {
+
+namespace {
+
+using Packet = ::webrtc::ForwardErrorCorrection::Packet;
+using ReceivedFecPacket = ::webrtc::ForwardErrorCorrection::ReceivedFecPacket;
+
+// General. Assume single-stream protection.
+constexpr uint32_t kMediaSsrc = 1254983;
+constexpr uint16_t kMediaStartSeqNum = 825;
+constexpr size_t kMediaPacketLength = 1234;
+constexpr uint32_t kFlexfecSsrc = 52142;
+
+constexpr size_t kFlexfecHeaderSizes[] = {20, 24, 32};
+constexpr size_t kFlexfecPacketMaskOffset = 18;
+constexpr size_t kFlexfecPacketMaskSizes[] = {2, 6, 14};
+constexpr size_t kFlexfecMaxPacketSize = kFlexfecPacketMaskSizes[2];
+
+// Reader tests.
+constexpr uint8_t kNoFBit = 0 << 7;
+constexpr uint8_t kNoRBit = 0 << 6;
+constexpr uint8_t kPtRecov = 123;
+constexpr uint8_t kLengthRecov[] = {0xab, 0xcd};
+constexpr uint8_t kTsRecovery[] = {0x01, 0x23, 0x45, 0x67};
+constexpr uint8_t kSsrcCount = 1;
+constexpr uint8_t kReservedBits = 0x00;
+constexpr uint8_t kProtSsrc[] = {0x11, 0x22, 0x33, 0x44};
+constexpr uint8_t kSnBase[] = {0xaa, 0xbb};
+constexpr uint8_t kPayloadBits = 0x00;
+
+std::unique_ptr<uint8_t[]> GeneratePacketMask(size_t packet_mask_size,
+                                              uint64_t seed) {
+  Random random(seed);
+  std::unique_ptr<uint8_t[]> packet_mask(new uint8_t[kFlexfecMaxPacketSize]);
+  memset(packet_mask.get(), 0, kFlexfecMaxPacketSize);
+  for (size_t i = 0; i < packet_mask_size; ++i) {
+    packet_mask[i] = random.Rand<uint8_t>();
+  }
+  return packet_mask;
+}
+
+void ClearBit(size_t index, uint8_t* packet_mask) {
+  packet_mask[index / 8] &= ~(1 << (7 - index % 8));
+}
+
+void SetBit(size_t index, uint8_t* packet_mask) {
+  packet_mask[index / 8] |= (1 << (7 - index % 8));
+}
+
+rtc::scoped_refptr<Packet> WriteHeader(const uint8_t* packet_mask,
+                                       size_t packet_mask_size) {
+  FlexfecHeaderWriter writer;
+  rtc::scoped_refptr<Packet> written_packet(new Packet());
+  written_packet->length = kMediaPacketLength;
+  for (size_t i = 0; i < written_packet->length; ++i) {
+    written_packet->data[i] = i;  // Actual content doesn't matter.
+  }
+  writer.FinalizeFecHeader(kMediaSsrc, kMediaStartSeqNum, packet_mask,
+                           packet_mask_size, written_packet.get());
+  return written_packet;
+}
+
+std::unique_ptr<ReceivedFecPacket> ReadHeader(const Packet& written_packet) {
+  FlexfecHeaderReader reader;
+  std::unique_ptr<ReceivedFecPacket> read_packet(new ReceivedFecPacket());
+  read_packet->ssrc = kFlexfecSsrc;
+  read_packet->pkt = rtc::scoped_refptr<Packet>(new Packet());
+  memcpy(read_packet->pkt->data, written_packet.data, written_packet.length);
+  read_packet->pkt->length = written_packet.length;
+  EXPECT_TRUE(reader.ReadFecHeader(read_packet.get()));
+  return read_packet;
+}
+
+void VerifyReadHeaders(size_t expected_fec_header_size,
+                       const uint8_t* expected_packet_mask,
+                       size_t expected_packet_mask_size,
+                       const ReceivedFecPacket& read_packet) {
+  EXPECT_EQ(expected_fec_header_size, read_packet.fec_header_size);
+  EXPECT_EQ(ByteReader<uint32_t>::ReadBigEndian(kProtSsrc),
+            read_packet.protected_ssrc);
+  EXPECT_EQ(ByteReader<uint16_t>::ReadBigEndian(kSnBase),
+            read_packet.seq_num_base);
+  const size_t packet_mask_offset = read_packet.packet_mask_offset;
+  EXPECT_EQ(kFlexfecPacketMaskOffset, packet_mask_offset);
+  EXPECT_EQ(expected_packet_mask_size, read_packet.packet_mask_size);
+  EXPECT_EQ(read_packet.pkt->length - expected_fec_header_size,
+            read_packet.protection_length);
+  // Ensure that the K-bits are removed and the packet mask has been packed.
+  EXPECT_THAT(::testing::make_tuple(read_packet.pkt->data + packet_mask_offset,
+                                    read_packet.packet_mask_size),
+              ::testing::ElementsAreArray(expected_packet_mask,
+                                          expected_packet_mask_size));
+}
+
+void VerifyFinalizedHeaders(const uint8_t* expected_packet_mask,
+                            size_t expected_packet_mask_size,
+                            const Packet& written_packet) {
+  const uint8_t* packet = written_packet.data;
+  EXPECT_EQ(0x00, packet[0] & 0x80);  // F bit clear.
+  EXPECT_EQ(0x00, packet[0] & 0x40);  // R bit clear.
+  EXPECT_EQ(0x01, packet[8]);         // SSRCCount = 1.
+  EXPECT_EQ(kMediaSsrc, ByteReader<uint32_t>::ReadBigEndian(packet + 12));
+  EXPECT_EQ(kMediaStartSeqNum,
+            ByteReader<uint16_t>::ReadBigEndian(packet + 16));
+  EXPECT_THAT(::testing::make_tuple(packet + kFlexfecPacketMaskOffset,
+                                    expected_packet_mask_size),
+              ::testing::ElementsAreArray(expected_packet_mask,
+                                          expected_packet_mask_size));
+}
+
+void VerifyWrittenAndReadHeaders(size_t expected_fec_header_size,
+                                 const uint8_t* expected_packet_mask,
+                                 size_t expected_packet_mask_size,
+                                 const Packet& written_packet,
+                                 const ReceivedFecPacket& read_packet) {
+  EXPECT_EQ(kFlexfecSsrc, read_packet.ssrc);
+  EXPECT_EQ(expected_fec_header_size, read_packet.fec_header_size);
+  EXPECT_EQ(kMediaSsrc, read_packet.protected_ssrc);
+  EXPECT_EQ(kMediaStartSeqNum, read_packet.seq_num_base);
+  EXPECT_EQ(kFlexfecPacketMaskOffset, read_packet.packet_mask_offset);
+  ASSERT_EQ(expected_packet_mask_size, read_packet.packet_mask_size);
+  EXPECT_EQ(written_packet.length - expected_fec_header_size,
+            read_packet.protection_length);
+  // Verify that the call to ReadFecHeader did normalize the packet masks.
+  EXPECT_THAT(
+      ::testing::make_tuple(read_packet.pkt->data + kFlexfecPacketMaskOffset,
+                            read_packet.packet_mask_size),
+      ::testing::ElementsAreArray(expected_packet_mask,
+                                  expected_packet_mask_size));
+  // Verify that the call to ReadFecHeader did not tamper with the payload.
+  EXPECT_THAT(
+      ::testing::make_tuple(written_packet.data + expected_fec_header_size,

[danilchap, 2016/09/21 11:17:56]

may be swap here too (read_packet is tested, written_packet is expected value)

[brandtr, 2016/09/21 11:43:28]

Good idea, done.

+                            written_packet.length - expected_fec_header_size),
+      ::testing::ElementsAreArray(
+          read_packet.pkt->data + expected_fec_header_size,
+          written_packet.length - expected_fec_header_size));

[danilchap, 2016/09/21 11:17:56]

may be read_packet.pkt->length instead of written_packet.length?

[brandtr, 2016/09/21 11:43:28]

Switched to read |written_packet|, so not changing the length here.

+}
+
+}  // namespace
+
+TEST(FlexfecHeaderReaderTest, ReadsHeaderWithKBit0Set) {
+  constexpr uint8_t kKBit0 = 1 << 7;
+  constexpr size_t kExpectedPacketMaskSize = 2;
+  constexpr size_t kExpectedFecHeaderSize = 20;
+  // clang-format off
+  constexpr uint8_t kFlexfecPktMask[] = {kKBit0 | 0x08, 0x81};
+  constexpr uint8_t kUlpfecPacketMask[] =        {0x11, 0x02};
+  // clang-format on
+  constexpr uint8_t kPacketData[] = {
+      kNoFBit | kNoRBit, kPtRecov,       kLengthRecov[0],    kLengthRecov[1],

[danilchap, 2016/09/21 11:17:56]

may do not shortent since you have spaces for fuller name kPtRecovery

[brandtr, 2016/09/21 11:43:28]

Good point, done.

+      kTsRecovery[0],    kTsRecovery[1], kTsRecovery[2],     kTsRecovery[3],
+      kSsrcCount,        kReservedBits,  kReservedBits,      kReservedBits,
+      kProtSsrc[0],      kProtSsrc[1],   kProtSsrc[2],       kProtSsrc[3],
+      kSnBase[0],        kSnBase[1],     kFlexfecPktMask[0], kFlexfecPktMask[1],
+      kPayloadBits,      kPayloadBits,   kPayloadBits,       kPayloadBits};
+  const size_t packet_length = sizeof(kPacketData);
+  ReceivedFecPacket read_packet;
+  read_packet.pkt = rtc::scoped_refptr<Packet>(new Packet());
+  memcpy(read_packet.pkt->data, kPacketData, packet_length);
+  read_packet.pkt->length = packet_length;
+
+  FlexfecHeaderReader reader;
+  EXPECT_TRUE(reader.ReadFecHeader(&read_packet));
+
+  VerifyReadHeaders(kExpectedFecHeaderSize, kUlpfecPacketMask,
+                    kExpectedPacketMaskSize, read_packet);
+}
+
+TEST(FlexfecHeaderReaderTest, ReadsHeaderWithKBit1Set) {
+  constexpr uint8_t kKBit0 = 0 << 7;
+  constexpr uint8_t kKBit1 = 1 << 7;
+  constexpr size_t kExpectedPacketMaskSize = 6;
+  constexpr size_t kExpectedFecHeaderSize = 24;
+  // clang-format off
+  constexpr uint8_t kFlxfecPktMsk[] = {kKBit0 | 0x48, 0x81,
+                                       kKBit1 | 0x02, 0x11, 0x00, 0x21};
+  constexpr uint8_t kUlpfecPacketMask[] =      {0x91, 0x02,
+                                                0x08, 0x44, 0x00, 0x84};
+  // clang-format on
+  constexpr uint8_t kPacketData[] = {
+      kNoFBit | kNoRBit, kPtRecov,         kLengthRecov[0],  kLengthRecov[1],
+      kTsRecovery[0],    kTsRecovery[1],   kTsRecovery[2],   kTsRecovery[3],
+      kSsrcCount,        kReservedBits,    kReservedBits,    kReservedBits,
+      kProtSsrc[0],      kProtSsrc[1],     kProtSsrc[2],     kProtSsrc[3],
+      kSnBase[0],        kSnBase[1],       kFlxfecPktMsk[0], kFlxfecPktMsk[1],
+      kFlxfecPktMsk[2],  kFlxfecPktMsk[3], kFlxfecPktMsk[4], kFlxfecPktMsk[5],
+      kPayloadBits,      kPayloadBits,     kPayloadBits,     kPayloadBits};
+  const size_t packet_length = sizeof(kPacketData);
+  ReceivedFecPacket read_packet;
+  read_packet.pkt = rtc::scoped_refptr<Packet>(new Packet());
+  memcpy(read_packet.pkt->data, kPacketData, packet_length);
+  read_packet.pkt->length = packet_length;
+
+  FlexfecHeaderReader reader;
+  EXPECT_TRUE(reader.ReadFecHeader(&read_packet));
+
+  VerifyReadHeaders(kExpectedFecHeaderSize, kUlpfecPacketMask,
+                    kExpectedPacketMaskSize, read_packet);
+}
+
+TEST(FlexfecHeaderReaderTest, ReadsHeaderWithKBit2Set) {
+  constexpr uint8_t kKBit0 = 0 << 7;
+  constexpr uint8_t kKBit1 = 0 << 7;
+  constexpr uint8_t kKBit2 = 1 << 7;
+  constexpr size_t kExpectedPacketMaskSize = 14;
+  constexpr size_t kExpectedFecHeaderSize = 32;
+  // clang-format off
+  constexpr uint8_t kFlxfcPktMsk[] = {kKBit0 | 0x48, 0x81,
+                                      kKBit1 | 0x02, 0x11, 0x00, 0x21,
+                                      kKBit2 | 0x01, 0x11, 0x11, 0x11,
+                                               0x11, 0x11, 0x11, 0x11};
+  constexpr uint8_t kUlpfecPacketMask[] =     {0x91, 0x02,
+                                               0x08, 0x44, 0x00, 0x84,
+                                               0x08, 0x88, 0x88, 0x88,
+                                               0x88, 0x88, 0x88, 0x88};
+  // clang-format on
+  constexpr uint8_t kPacketData[] = {
+      kNoFBit | kNoRBit, kPtRecov,         kLengthRecov[0],  kLengthRecov[1],
+      kTsRecovery[0],    kTsRecovery[1],   kTsRecovery[2],   kTsRecovery[3],
+      kSsrcCount,        kReservedBits,    kReservedBits,    kReservedBits,
+      kProtSsrc[0],      kProtSsrc[1],     kProtSsrc[2],     kProtSsrc[3],
+      kSnBase[0],        kSnBase[1],       kFlxfcPktMsk[0],  kFlxfcPktMsk[1],
+      kFlxfcPktMsk[2],   kFlxfcPktMsk[3],  kFlxfcPktMsk[4],  kFlxfcPktMsk[5],
+      kFlxfcPktMsk[6],   kFlxfcPktMsk[7],  kFlxfcPktMsk[8],  kFlxfcPktMsk[9],
+      kFlxfcPktMsk[10],  kFlxfcPktMsk[11], kFlxfcPktMsk[12], kFlxfcPktMsk[13],
+      kPayloadBits,      kPayloadBits,     kPayloadBits,     kPayloadBits};
+  const size_t packet_length = sizeof(kPacketData);
+  ReceivedFecPacket read_packet;
+  read_packet.pkt = rtc::scoped_refptr<Packet>(new Packet());
+  memcpy(read_packet.pkt->data, kPacketData, packet_length);
+  read_packet.pkt->length = packet_length;
+
+  FlexfecHeaderReader reader;
+  EXPECT_TRUE(reader.ReadFecHeader(&read_packet));
+
+  VerifyReadHeaders(kExpectedFecHeaderSize, kUlpfecPacketMask,
+                    kExpectedPacketMaskSize, read_packet);
+}
+
+TEST(FlexfecHeaderReaderTest, ReadPacketWithoutStreamSpecificHeaderShouldFail) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+
+  // Simulate short received packet.
+  ReceivedFecPacket read_packet;
+  read_packet.ssrc = kFlexfecSsrc;
+  read_packet.pkt = std::move(written_packet);
+  read_packet.pkt->length = 12;
+
+  FlexfecHeaderReader reader;
+  EXPECT_FALSE(reader.ReadFecHeader(&read_packet));
+}
+
+TEST(FlexfecHeaderReaderTest, ReadShortPacketWithKBit0SetShouldFail) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+
+  // Simulate short received packet.
+  ReceivedFecPacket read_packet;
+  read_packet.ssrc = kFlexfecSsrc;
+  read_packet.pkt = std::move(written_packet);
+  read_packet.pkt->length = 18;
+
+  FlexfecHeaderReader reader;
+  EXPECT_FALSE(reader.ReadFecHeader(&read_packet));
+}
+
+TEST(FlexfecHeaderReaderTest, ReadShortPacketWithKBit1SetShouldFail) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(15, packet_mask.get());  // This expands the packet mask "once".
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+
+  // Simulate short received packet.
+  ReceivedFecPacket read_packet;
+  read_packet.ssrc = kFlexfecSsrc;
+  read_packet.pkt = std::move(written_packet);
+  read_packet.pkt->length = 20;
+
+  FlexfecHeaderReader reader;
+  EXPECT_FALSE(reader.ReadFecHeader(&read_packet));
+}
+
+TEST(FlexfecHeaderReaderTest, ReadShortPacketWithKBit2SetShouldFail) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(47, packet_mask.get());  // This expands the packet mask "twice".
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+
+  // Simulate short received packet.
+  ReceivedFecPacket read_packet;
+  read_packet.ssrc = kFlexfecSsrc;
+  read_packet.pkt = std::move(written_packet);
+  read_packet.pkt->length = 24;
+
+  FlexfecHeaderReader reader;
+  EXPECT_FALSE(reader.ReadFecHeader(&read_packet));
+}
+
+TEST(FlexfecHeaderWriterTest, FinalizesHeaderWithKBit0Set) {
+  constexpr size_t kExpectedPacketMaskSize = 2;
+  constexpr uint8_t kFlexfecPacketMask[] = {0x88, 0x81};
+  constexpr uint8_t kUlpfecPacketMask[] = {0x11, 0x02};
+  Packet written_packet;
+  written_packet.length = kMediaPacketLength;
+  for (size_t i = 0; i < written_packet.length; ++i) {
+    written_packet.data[i] = i;
+  }
+
+  FlexfecHeaderWriter writer;
+  writer.FinalizeFecHeader(kMediaSsrc, kMediaStartSeqNum, kUlpfecPacketMask,
+                           sizeof(kUlpfecPacketMask), &written_packet);
+
+  VerifyFinalizedHeaders(kFlexfecPacketMask, kExpectedPacketMaskSize,
+                         written_packet);
+}
+
+TEST(FlexfecHeaderWriterTest, FinalizesHeaderWithKBit1Set) {
+  constexpr size_t kExpectedPacketMaskSize = 6;
+  constexpr uint8_t kFlexfecPacketMask[] = {0x48, 0x81, 0x82, 0x11, 0x00, 0x21};
+  constexpr uint8_t kUlpfecPacketMask[] = {0x91, 0x02, 0x08, 0x44, 0x00, 0x84};
+  Packet written_packet;
+  written_packet.length = kMediaPacketLength;
+  for (size_t i = 0; i < written_packet.length; ++i) {
+    written_packet.data[i] = i;
+  }
+
+  FlexfecHeaderWriter writer;
+  writer.FinalizeFecHeader(kMediaSsrc, kMediaStartSeqNum, kUlpfecPacketMask,
+                           sizeof(kUlpfecPacketMask), &written_packet);
+
+  VerifyFinalizedHeaders(kFlexfecPacketMask, kExpectedPacketMaskSize,
+                         written_packet);
+}
+
+TEST(FlexfecHeaderWriterTest, FinalizesHeaderWithKBit2Set) {
+  constexpr size_t kExpectedPacketMaskSize = 14;
+  constexpr uint8_t kFlexfecPacketMask[] = {
+      0x11, 0x11,                                     // K-bit 0 clear.
+      0x11, 0x11, 0x11, 0x10,                         // K-bit 1 clear.
+      0xa0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00  // K-bit 2 set.
+  };
+  constexpr uint8_t kUlpfecPacketMask[] = {0x22, 0x22, 0x44, 0x44, 0x44, 0x41};
+  Packet written_packet;
+  written_packet.length = kMediaPacketLength;
+  for (size_t i = 0; i < written_packet.length; ++i) {
+    written_packet.data[i] = i;
+  }
+
+  FlexfecHeaderWriter writer;
+  writer.FinalizeFecHeader(kMediaSsrc, kMediaStartSeqNum, kUlpfecPacketMask,
+                           sizeof(kUlpfecPacketMask), &written_packet);
+
+  VerifyFinalizedHeaders(kFlexfecPacketMask, kExpectedPacketMaskSize,
+                         written_packet);
+}
+
+TEST(FlexfecHeaderWriterTest, ContractsShortUlpfecPacketMaskWithBit15Clear) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(15, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[0], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[0], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderWriterTest, ExpandsShortUlpfecPacketMaskWithBit15Set) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(15, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[1], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[1], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderWriterTest,
+     ContractsLongUlpfecPacketMaskWithBit46And47Clear) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(46, packet_mask.get());
+  ClearBit(47, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[1], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[1], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderWriterTest, ExpandsLongUlpfecPacketMaskWithBit46And47Clear) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(46, packet_mask.get());
+  ClearBit(47, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[2], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[2], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderWriterTest,
+     ExpandsLongUlpfecPacketMaskWithBit46ClearBit47Set) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(46, packet_mask.get());
+  SetBit(47, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[2], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[2], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderWriterTest, ExpandsLongUlpfecPacketMaskWithBit46And47Set) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(46, packet_mask.get());
+  SetBit(47, packet_mask.get());
+
+  FlexfecHeaderWriter writer;
+  size_t min_packet_mask_size =
+      writer.MinPacketMaskSize(packet_mask.get(), packet_mask_size);
+
+  EXPECT_EQ(kFlexfecPacketMaskSizes[2], min_packet_mask_size);
+  EXPECT_EQ(kFlexfecHeaderSizes[2], writer.FecHeaderSize(min_packet_mask_size));
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadSmallUlpfecPacketHeaderWithMaskKBit15Clear) {

[danilchap, 2016/09/21 11:17:55]

KBit15? wasn't K prefix just for the 1st bits in each of the 3 packet mask
blocks

[brandtr, 2016/09/21 11:43:28]

This was a search-and-replace error :(

...WithMas_kBit_15...

Thanks for noticing!

+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(15, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[0], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[0], *written_packet,
+                              *read_packet);
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadSmallUlpfecPacketHeaderWithMaskKBit15Set) {

[danilchap, 2016/09/21 11:17:56]

same here

[brandtr, 2016/09/21 11:43:28]

Done.

+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitClear;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(15, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[1], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[1], *written_packet,
+                              *read_packet);
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadLargeUlpfecPacketHeaderWithMaskBits46And47Clear) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(46, packet_mask.get());
+  ClearBit(47, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[1], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[1], *written_packet,
+                              *read_packet);
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadLargeUlpfecPacketHeaderWithMaskBit46SetBit47Clear) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(46, packet_mask.get());
+  ClearBit(47, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[2], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[2], *written_packet,
+                              *read_packet);
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadLargeUlpfecPacketHeaderMaskWithBit46ClearBit47Set) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  ClearBit(46, packet_mask.get());
+  SetBit(47, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[2], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[2], *written_packet,
+                              *read_packet);
+}
+
+TEST(FlexfecHeaderReaderWriterTest,
+     WriteAndReadLargeUlpfecPacketHeaderWithMaskBits46And47Set) {
+  const size_t packet_mask_size = kUlpfecPacketMaskSizeLBitSet;
+  auto packet_mask = GeneratePacketMask(packet_mask_size, 0xabcd);
+  SetBit(46, packet_mask.get());
+  SetBit(47, packet_mask.get());
+
+  auto written_packet = WriteHeader(packet_mask.get(), packet_mask_size);
+  auto read_packet = ReadHeader(*written_packet);
+
+  VerifyWrittenAndReadHeaders(kFlexfecHeaderSizes[2], packet_mask.get(),
+                              kFlexfecPacketMaskSizes[2], *written_packet,
+                              *read_packet);
+}
+
+}  // namespace webrtc