webrtc/RTCPeerConnection-setLocalDescription-pranswer.html

<!doctype html>
<meta charset=utf-8>
<title>RTCPeerConnection.prototype.setLocalDescription pranswer</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="RTCPeerConnection-helper.js"></script>
<script>
  'use strict';

  // Test is based on the following editor draft:
  // https://w3c.github.io/webrtc-pc/archives/20170605/webrtc.html

  // The following helper functions are called from RTCPeerConnection-helper.js:
  //   assert_session_desc_similar

  /*
    4.3.2.  Interface Definition
      [Constructor(optional RTCConfiguration configuration)]
      interface RTCPeerConnection : EventTarget {
        Promise<void>                      setLocalDescription(
            RTCSessionDescriptionInit description);

        readonly attribute RTCSessionDescription? localDescription;
        readonly attribute RTCSessionDescription? currentLocalDescription;
        readonly attribute RTCSessionDescription? pendingLocalDescription;

        Promise<void>                      setRemoteDescription(
            RTCSessionDescriptionInit description);

        readonly attribute RTCSessionDescription? remoteDescription;
        readonly attribute RTCSessionDescription? currentRemoteDescription;
        readonly attribute RTCSessionDescription? pendingRemoteDescription;
        ...
      };

    4.6.2.  RTCSessionDescription Class
      dictionary RTCSessionDescriptionInit {
        required RTCSdpType type;
                 DOMString  sdp = "";
      };

    4.6.1.  RTCSdpType
      enum RTCSdpType {
        "offer",
        "pranswer",
        "answer",
        "rollback"
      };
   */

  /*
    4.3.1.6.  Set the RTCSessionSessionDescription
      2.3.  If the description's type is invalid for the current signaling state of
            connection, then reject p with a newly created InvalidStateError and abort
            these steps.

    [jsep]
      5.5. If the type is "pranswer" or "answer", the PeerConnection
           state MUST be either "have-remote-offer" or "have-local-pranswer".
   */
  promise_test(t => {
    const pc = new RTCPeerConnection();

    t.add_cleanup(() => pc.close());

    return pc.createOffer()
    .then(offer =>
      promise_rejects_dom(t, 'InvalidStateError',
        pc.setLocalDescription({ type: 'pranswer', sdp: offer.sdp })));
  }, 'setLocalDescription(pranswer) from stable state should reject with InvalidStateError');

  /*
    4.3.1.6 Set the RTCSessionSessionDescription
      2.2.2.  If description is set as a local description, then run one of the
              following steps:
        - If description is of type "pranswer", then set
          connection.pendingLocalDescription to description and signaling state to
          have-local-pranswer.
   */
  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());

    const states = [];
    pc.addEventListener('signalingstatechange', () => states.push(pc.signalingState));

    return generateVideoReceiveOnlyOffer(pc)
    .then(offer =>
      pc.setRemoteDescription(offer)
      .then(() => pc.createAnswer())
      .then(answer => {
        const pranswer = { type: 'pranswer', sdp: answer.sdp };

        return pc.setLocalDescription(pranswer)
        .then(() => {
          assert_equals(pc.signalingState, 'have-local-pranswer');

          assert_session_desc_similar(pc.remoteDescription, offer);
          assert_session_desc_similar(pc.pendingRemoteDescription, offer);
          assert_equals(pc.currentRemoteDescription, null);

          assert_session_desc_similar(pc.localDescription, pranswer);
          assert_session_desc_similar(pc.pendingLocalDescription, pranswer);
          assert_equals(pc.currentLocalDescription, null);


          assert_array_equals(states, ['have-remote-offer', 'have-local-pranswer']);
        });
      }));
  }, 'setLocalDescription(pranswer) should succeed');

  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());

    const states = [];
    pc.addEventListener('signalingstatechange', () => states.push(pc.signalingState));

    return generateVideoReceiveOnlyOffer(pc)
    .then(offer =>
      pc.setRemoteDescription(offer)
      .then(() => pc.createAnswer())
      .then(answer => {
        const pranswer = { type: 'pranswer', sdp: answer.sdp };

        return pc.setLocalDescription(pranswer)
        .then(() => pc.setLocalDescription(pranswer))
        .then(() => {
          assert_array_equals(states, ['have-remote-offer', 'have-local-pranswer']);
        });
      }));
  }, 'setLocalDescription(pranswer) can be applied multiple times while still in have-local-pranswer');

  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());

    const states = [];
    pc.addEventListener('signalingstatechange', () => states.push(pc.signalingState));

    return generateVideoReceiveOnlyOffer(pc)
    .then(offer =>
      pc.setRemoteDescription(offer)
      .then(() => pc.createAnswer())
      .then(answer => {
        const pranswer = { type: 'pranswer', sdp: answer.sdp };

        return pc.setLocalDescription(pranswer)
        .then(() => pc.setLocalDescription(answer))
        .then(() => {
          assert_equals(pc.signalingState, 'stable');
          assert_session_desc_similar(pc.localDescription, answer);
          assert_session_desc_similar(pc.remoteDescription, offer);

          assert_session_desc_similar(pc.currentLocalDescription, answer);
          assert_session_desc_similar(pc.currentRemoteDescription, offer);

          assert_equals(pc.pendingLocalDescription, null);
          assert_equals(pc.pendingRemoteDescription, null);

          assert_array_equals(states, ['have-remote-offer', 'have-local-pranswer', 'stable']);
        });
      }));
  }, 'setLocalDescription(answer) from have-local-pranswer state should succeed');

</script>