Use the same draft version in SDP data channel answers as used in the offer.

webrtc/pc/mediasession_unittest.cc

 /*
  *  Copyright 2004 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 951 matching lines @@
   EXPECT_TRUE(acd->rtcp_mux());                 // negotiated rtcp-mux
   ASSERT_CRYPTO(acd, 1U, CS_AEAD_AES_256_GCM);
   EXPECT_EQ(MEDIA_TYPE_DATA, vcd->type());
   EXPECT_EQ(MAKE_VECTOR(kDataCodecsAnswer), vcd->codecs());
   EXPECT_NE(0U, vcd->first_ssrc());             // a random nonzero ssrc
   EXPECT_TRUE(vcd->rtcp_mux());                 // negotiated rtcp-mux
   ASSERT_CRYPTO(vcd, 1U, CS_AEAD_AES_256_GCM);
   EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), vcd->protocol());
 }
 
+TEST_F(MediaSessionDescriptionFactoryTest, TestCreateDataAnswerUsesSctpmap) {

[Taylor Brandstetter, 2017/02/17 22:15:35]

Could you leave a comment above these two tests describing what they're testing
from a high level? For example, "Test that the use_sctpmap flag in an answer,
representing whether or not SDP will use legacy 'a=sctpmap' attributes, matches
the flag in the offer."

[Zach Stein, 2017/02/17 22:55:28]

Done.

+  MediaSessionOptions opts;
+  opts.data_channel_type = cricket::DCT_SCTP;
+  std::unique_ptr<SessionDescription> offer(f1_.CreateOffer(opts, NULL));

[Taylor Brandstetter, 2017/02/17 22:15:35]

We use C++11 "nullptr" instead of "NULL". Though don't worry about changing it
in this CL; I'm going to run a script to convert every "NULL" to "nullptr" some
time soon. https://codereview.webrtc.org/2685783014/

[Zach Stein, 2017/02/17 22:55:28]

I'll match the rest of the file for now.

+  ASSERT_TRUE(offer.get() != NULL);
+  ContentInfo* offer_dv = offer->GetContentByName("data");

[Taylor Brandstetter, 2017/02/17 22:15:35]

What does "dv" stand for?

I'd suggest more descriptive names, such as "offer_data_content",
"offer_data_description", though it matters less in a unit test.

[Zach Stein, 2017/02/17 22:55:28]

I meant for this to be dc for data content - I'll change it to that. This
matches the rest of the file. The test above uses vc instead of dc - I'll fix
that one too. I would rather not change the entire file here though, so I'll
stick with dc instead of data_content for now.

+  ASSERT_TRUE(offer_dv != NULL);
+  DataContentDescription* offer_dvd =
+      static_cast<DataContentDescription*>(offer_dv->description);
+  EXPECT_TRUE(offer_dvd->use_sctpmap());
+
+  std::unique_ptr<SessionDescription> answer(
+      f2_.CreateAnswer(offer.get(), opts, NULL));
+  const ContentInfo* answer_dv = answer->GetContentByName("data");
+  ASSERT_TRUE(answer_dv != NULL);
+  const DataContentDescription* answer_dvd =
+      static_cast<const DataContentDescription*>(answer_dv->description);
+  EXPECT_TRUE(answer_dvd->use_sctpmap());
+}
+
+TEST_F(MediaSessionDescriptionFactoryTest, TestCreateDataAnswerWithoutSctpmap) {
+  MediaSessionOptions opts;
+  opts.data_channel_type = cricket::DCT_SCTP;
+  std::unique_ptr<SessionDescription> offer(f1_.CreateOffer(opts, NULL));
+  ASSERT_TRUE(offer.get() != NULL);
+  ContentInfo* offer_dv = offer->GetContentByName("data");
+  ASSERT_TRUE(offer_dv != NULL);
+  DataContentDescription* offer_dvd =
+      static_cast<DataContentDescription*>(offer_dv->description);
+  offer_dvd->set_use_sctpmap(false);
+
+  std::unique_ptr<SessionDescription> answer(
+      f2_.CreateAnswer(offer.get(), opts, NULL));
+  const ContentInfo* answer_dv = answer->GetContentByName("data");
+  ASSERT_TRUE(answer_dv != NULL);
+  const DataContentDescription* answer_dvd =
+      static_cast<const DataContentDescription*>(answer_dv->description);
+  EXPECT_FALSE(answer_dvd->use_sctpmap());
+}
+
 // Verifies that the order of the media contents in the offer is preserved in
 // the answer.
 TEST_F(MediaSessionDescriptionFactoryTest, TestCreateAnswerContentOrder) {
   MediaSessionOptions opts;
 
   // Creates a data only offer.
   opts.recv_audio = false;
   opts.data_channel_type = cricket::DCT_SCTP;
   std::unique_ptr<SessionDescription> offer1(f1_.CreateOffer(opts, NULL));
   ASSERT_TRUE(offer1.get() != NULL);
@@ skipping 1998 matching lines @@
                         ::testing::Combine(
                              ::testing::Values(cricket::MD_SENDONLY,
                                                cricket::MD_RECVONLY,
                                                cricket::MD_SENDRECV,
                                                cricket::MD_INACTIVE),
                              ::testing::Values(cricket::MD_SENDONLY,
                                                cricket::MD_RECVONLY,
                                                cricket::MD_SENDRECV,
                                                cricket::MD_INACTIVE),
                              ::testing::Bool()));