Add statistics gathering for packet loss.

webrtc/modules/rtp_rtcp/source/packet_loss_stats_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/packet_loss_stats_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/packet_loss_stats_unittest.cc b/webrtc/modules/rtp_rtcp/source/packet_loss_stats_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..660628242d10491cdcb14b6ef2b50389640d8cf3
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/packet_loss_stats_unittest.cc
@@ -0,0 +1,197 @@
+/*
+ *  Copyright (c) 2015 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 "testing/gtest/include/gtest/gtest.h"
+#include "webrtc/modules/rtp_rtcp/source/packet_loss_stats.h"
+
+namespace webrtc {
+
+class PacketLossStatsTest : public ::testing::Test {
+ protected:
+  PacketLossStats stats_;
+};
+
+// Add a lost packet as every other packet, they should all count as single
+// losses.
+TEST_F(PacketLossStatsTest, EveryOtherPacket) {
+  for (int i = 0; i < 1000; i += 2) {
+    stats_.AddLostPacket(i);
+  }
+  EXPECT_EQ(500, stats_.GetSingleLossCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossPacketCount());
+}
+
+// Add a lost packet as every other packet, but such that the sequence numbers
+// will wrap around while they are being added.
+TEST_F(PacketLossStatsTest, EveryOtherPacketWrapped) {
+  for (int i = 65500; i < 66500; i += 2) {
+    stats_.AddLostPacket(i & 0xFFFF);

[noahric, 2015/06/26 00:21:19]

Consider adding a CHECK or DCHECK in AddLostPacket to ensure the value fits in
the normal ssrc range. Otherwise, will weird things happen?

[bcornell, 2015/06/30 19:47:45]

AddLostPacket takes a uint16_t, I just like to be explicit with these tests
using ints that it is being masked into a 16 bit type.

+  }
+  EXPECT_EQ(500, stats_.GetSingleLossCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossPacketCount());
+}
+
+// Add a lost packet as every other packet, but such that the sequence numbers
+// will wrap around close to the very end, such that the buffer contains packets
+// on either side of the wrapping.
+TEST_F(PacketLossStatsTest, EveryOtherPacketWrappedAtEnd) {
+  for (int i = 64600; i < 65600; i += 2) {
+    stats_.AddLostPacket(i & 0xFFFF);
+  }
+  EXPECT_EQ(500, stats_.GetSingleLossCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(0, stats_.GetMultipleLossPacketCount());
+}
+
+// Add a lost packet as the first three of every eight packets. Each set of
+// three should count as a multiple loss event and three multiple loss packets.
+TEST_F(PacketLossStatsTest, FirstThreeOfEight) {
+  for (int i = 0; i < 1000; ++i) {
+    if ((i & 7) < 3) {
+      stats_.AddLostPacket(i);
+    }
+  }
+  EXPECT_EQ(0, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add a lost packet as the first three of every eight packets such that the
+// sequence numbers wrap in the middle of adding them.
+TEST_F(PacketLossStatsTest, FirstThreeOfEightWrapped) {
+  for (int i = 65500; i < 66500; ++i) {
+    if ((i & 7) < 3) {
+      stats_.AddLostPacket(i & 0xFFFF);
+    }
+  }
+  EXPECT_EQ(0, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add a lost packet as the first three of every eight packets such that the
+// sequence numbers wrap near the end of adding them and there are still numbers
+// in the buffer from before the wrapping.
+TEST_F(PacketLossStatsTest, FirstThreeOfEightWrappedAtEnd) {
+  for (int i = 64600; i < 65600; ++i) {
+    if ((i & 7) < 3) {
+      stats_.AddLostPacket(i & 0xFFFF);
+    }
+  }
+  EXPECT_EQ(0, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets as the first three and the fifth of every eight packets. The
+// set of three should be multiple loss and the fifth should be single loss.
+TEST_F(PacketLossStatsTest, FirstThreeAndFifthOfEight) {
+  for (int i = 0; i < 1000; ++i) {
+    if ((i & 7) < 3 || (i & 7) == 4) {
+      stats_.AddLostPacket(i);
+    }
+  }
+  EXPECT_EQ(125, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets as the first three and the fifth of every eight packets such
+// that the sequence numbers wrap in the middle of adding them.
+TEST_F(PacketLossStatsTest, FirstThreeAndFifthOfEightWrapped) {
+  for (int i = 65500; i < 66500; ++i) {
+    if ((i & 7) < 3 || (i & 7) == 4) {
+      stats_.AddLostPacket(i & 0xFFFF);
+    }
+  }
+  EXPECT_EQ(125, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets as the first three and the fifth of every eight packets such
+// that the sequence numbers wrap near the end of adding them and there are
+// packets from before the wrapping still in the buffer.
+TEST_F(PacketLossStatsTest, FirstThreeAndFifthOfEightWrappedAtEnd) {
+  for (int i = 64600; i < 65600; ++i) {
+    if ((i & 7) < 3 || (i & 7) == 4) {
+      stats_.AddLostPacket(i & 0xFFFF);
+    }
+  }
+  EXPECT_EQ(125, stats_.GetSingleLossCount());
+  EXPECT_EQ(125, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(375, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets such that there is a multiple loss event that continues
+// around the wrapping of sequence numbers.
+TEST_F(PacketLossStatsTest, MultipleLossEventWrapped) {
+  for (int i = 60000; i < 60500; i += 2) {
+    stats_.AddLostPacket(i);
+  }
+  for (int i = 65530; i < 65540; ++i) {
+    stats_.AddLostPacket(i & 0xFFFF);
+  }
+  EXPECT_EQ(250, stats_.GetSingleLossCount());
+  EXPECT_EQ(1, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(10, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets such that there is a multiple loss event that continues
+// around the wrapping of sequence numbers and then is pushed out of the buffer.
+TEST_F(PacketLossStatsTest, MultipleLossEventWrappedPushedOut) {
+  for (int i = 60000; i < 60500; i += 2) {
+    stats_.AddLostPacket(i);
+  }
+  for (int i = 65530; i < 65540; ++i) {
+    stats_.AddLostPacket(i & 0xFFFF);
+  }
+  for (int i = 1000; i < 1500; i += 2) {
+    stats_.AddLostPacket(i);
+  }
+  EXPECT_EQ(500, stats_.GetSingleLossCount());
+  EXPECT_EQ(1, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(10, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets out of order and ensure that they still get counted
+// correctly as single or multiple loss events.
+TEST_F(PacketLossStatsTest, OutOfOrder) {
+  for (int i = 0; i < 1000; i += 10) {
+    stats_.AddLostPacket(i + 5);
+    stats_.AddLostPacket(i + 7);
+    stats_.AddLostPacket(i + 4);
+    stats_.AddLostPacket(i + 1);
+    stats_.AddLostPacket(i + 2);
+  }
+  EXPECT_EQ(100, stats_.GetSingleLossCount());
+  EXPECT_EQ(200, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(400, stats_.GetMultipleLossPacketCount());
+}
+
+// Add loss packets out of order and ensure that they still get counted
+// correctly as single or multiple loss events, and wrap in the middle of
+// adding.
+TEST_F(PacketLossStatsTest, OutOfOrderWrapped) {
+  for (int i = 65000; i < 66000; i += 10) {
+    stats_.AddLostPacket((i + 5) & 0xFFFF);
+    stats_.AddLostPacket((i + 7) & 0xFFFF);
+    stats_.AddLostPacket((i + 4) & 0xFFFF);
+    stats_.AddLostPacket((i + 1) & 0xFFFF);
+    stats_.AddLostPacket((i + 2) & 0xFFFF);
+  }
+  EXPECT_EQ(100, stats_.GetSingleLossCount());
+  EXPECT_EQ(200, stats_.GetMultipleLossEventCount());
+  EXPECT_EQ(400, stats_.GetMultipleLossPacketCount());
+}
+
+}  // namespace webrtc