Add FEC producer fuzzing and a unittest for one of the issues found.

webrtc/modules/rtp_rtcp/source/producer_fec_unittest.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 36 matching lines @@
   virtual void TearDown() {
     delete producer_;
     delete fec_;
     delete generator_;
   }
   ForwardErrorCorrection* fec_;
   ProducerFec* producer_;
   FrameGenerator* generator_;
 };
 
+TEST_F(ProducerFecTest, FuzzOneInput) {
+  uint8_t data[] = {
+      0xf9, 0x36, 0x70, 0xc2, 0xfb, 0x28, 0x21, 0x21, 0x47, 0x3b, 0x36, 0x70,
+      0xca, 0xcf, 0xff, 0x21, 0x21, 0x45, 0x3b, 0xb6, 0x2a, 0x27, 0xd6, 0x3a,
+      0xa2, 0x27, 0x21, 0x5c, 0x3a, 0x49, 0x9b, 0x1b, 0x29, 0x84, 0x3a, 0x3a,
+      0x27, 0x54, 0x58, 0x3b, 0x28, 0xf4, 0x28, 0x27, 0x3b, 0x21, 0x3b, 0x3a,
+      0xcb, 0xc0, 0xc7, 0x29, 0x21, 0x76, 0xe6, 0x28, 0x7d, 0x97, 0x2a, 0x28,
+      0x7d, 0x28, 0x97, 0x2a, 0x29, 0x64, 0x3b, 0x1d, 0x7d, 0x56, 0xc7, 0x21,
+      0xd9, 0x12, 0x55, 0xa5, 0x28, 0x7d, 0x97, 0x2a, 0x28, 0x7d, 0x28, 0x97,
+      0x2a, 0x29, 0x64, 0x3b, 0x1d, 0x7d, 0x56, 0xc7, 0x5,  0xd9, 0x12, 0x79,
+      0x55, 0xa5, 0x56, 0xfe, 0x3a, 0x3,  0x37, 0x3b, 0x3a, 0x2a, 0x2a, 0xc7,
+      0x2c, 0x3a, 0xd1, 0xa2, 0x2a, 0x90, 0x2c, 0x21, 0x2a, 0x3b, 0x28, 0x8b,
+      0xfc, 0x3b, 0x46, 0x3b, 0xa2, 0x3b, 0x3b, 0x2a, 0x3b, 0x3b, 0x28, 0x29,
+      0xe,  0x3a, 0x2a, 0xa2, 0x46, 0x8b, 0x28, 0xff, 0x29, 0x29, 0x1,  0x8f,
+      0x9,  0x74, 0x57, 0x2a, 0x34, 0x3b, 0x3b, 0x3,  0xf0, 0x87, 0x3b, 0xfc,
+      0x5e, 0x29, 0x3b, 0x5c, 0x1a, 0xf8, 0x28, 0xcd, 0xe3, 0x98, 0x84, 0x7f,
+      0x87, 0x5f, 0x3a, 0x64, 0x1f, 0x28, 0x3b, 0x1d, 0x7d, 0x96, 0xf0, 0xc7};
+  FuzzOneInput(data, sizeof(data));

[pbos-webrtc, 2015/12/11 13:31:45]

Could you unpack this test to have the actual meaning of the data? If you change
the fuzzer in any way you lose test coverage now.

Also it confuses me that this test even links with FuzzOneInput right now? I
don't think the test name makes sense either. Is this test case for a large
sequence-number gap? If so do that? :)

[stefan-webrtc, 2015/12/11 14:26:26]

Done.

+}
+
 TEST_F(ProducerFecTest, OneFrameFec) {
   // The number of media packets (|kNumPackets|), number of frames (one for
   // this test), and the protection factor (|params->fec_rate|) are set to make
   // sure the conditions for generating FEC are satisfied. This means:
   // (1) protection factor is high enough so that actual overhead over 1 frame
   // of packets is within |kMaxExcessOverhead|, and (2) the total number of
   // media packets for 1 frame is at least |minimum_media_packets_fec_|.
   const int kNumPackets = 4;
   FecProtectionParams params = {15, false, 3};
   std::list<RtpPacket*> rtp_packets;
@@ skipping 80 matching lines @@
                kRedPayloadType,
                packet->header.header.payloadType,
                red_packet.get(),
                true);  // Marker bit set.
   for (int i = 0; i < 10; ++i)
     EXPECT_EQ(i, red_packet->data()[kRtpHeaderSize + 1 + i]);
   delete packet;
 }
 
 }  // namespace webrtc