webrtc/RTCPeerConnection-setLocalDescription-offer.html

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<meta charset=utf-8>
<meta name="variant" content="?interop-2026">
<meta name="variant" content="?rest">
<title>RTCPeerConnection.prototype.setLocalDescription</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="RTCPeerConnection-helper.js"></script>
<script>
'use strict';
const rest = !new URLSearchParams(location.search).has("interop-2026");
const interop2026 = !new URLSearchParams(location.search).has("rest");

  // 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:
  //   generateDataChannelOffer
  //   assert_session_desc_not_similar
  //   assert_session_desc_similar

  /*
    4.3.2.  Interface Definition
      [Constructor(optional RTCConfiguration configuration)]
      interface RTCPeerConnection : EventTarget {
        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"
      };
   */

if (rest) {
  /*
    4.3.2.  setLocalDescription
      2.  Let lastOffer be the result returned by the last call to createOffer.
      5.  If description.sdp is null and description.type is offer, set description.sdp
          to lastOffer.

    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 "offer", set connection.pendingLocalDescription
          to description and signaling state to have-local-offer.
   */
  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());

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

    return generateAudioReceiveOnlyOffer(pc)
    .then(offer =>
      pc.setLocalDescription(offer)
      .then(() => {
        assert_equals(pc.signalingState, 'have-local-offer');
        assert_session_desc_similar(pc.localDescription, offer);
        assert_equals(pc.pendingLocalDescription, pc.localDescription);
        assert_equals(pc.currentLocalDescription, null);

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

  /*
    4.3.2.  setLocalDescription
      2.  Let lastOffer be the result returned by the last call to createOffer.
      5.  If description.sdp is null and description.type is offer, set description.sdp
          to lastOffer.
   */
  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());
    return generateAudioReceiveOnlyOffer(pc)
    .then(offer =>
      pc.setLocalDescription({ type: 'offer' })
      .then(() => {
        assert_equals(pc.signalingState, 'have-local-offer');
        assert_session_desc_similar(pc.localDescription, offer);
        assert_equals(pc.pendingLocalDescription, pc.localDescription);
        assert_equals(pc.currentLocalDescription, null);
      }));
  }, 'setLocalDescription with type offer and null sdp should use lastOffer generated from createOffer');
} // rest

  /*
    4.3.2.  setLocalDescription
      2.  Let lastOffer be the result returned by the last call to createOffer.
      6.  If description.type is offer and description.sdp does not match lastOffer,
          reject the promise with a newly created InvalidModificationError and abort
          these steps.
   */
if (interop2026) {
  promise_test(t => {
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());
    const pc2 = new RTCPeerConnection();

    t.add_cleanup(() => pc2.close());

    return generateDataChannelOffer(pc)
    .then(offer => pc2.setLocalDescription(offer))
    .then(() => t.unreached_func("setLocalDescription should have rejected"),
          (error) => assert_equals(error.name, 'InvalidModificationError'));
  }, 'setLocalDescription() with offer not created by own createOffer() should reject with InvalidModificationError');
} // interop2026

if (rest) {
  promise_test(t => {
    // Create first offer with audio line, then second offer with
    // both audio and video line. Since the second offer is the
    // last offer, setLocalDescription would reject when setting
    // with the first offer
    const pc = new RTCPeerConnection();
    t.add_cleanup(() => pc.close());
    return generateAudioReceiveOnlyOffer(pc)
    .then(offer1 =>
      generateVideoReceiveOnlyOffer(pc)
      .then(offer2 => {
        assert_session_desc_not_similar(offer1, offer2);
        return promise_rejects_dom(t, 'InvalidModificationError',
          pc.setLocalDescription(offer1));
      }));
  }, 'Set created offer other than last offer should reject with InvalidModificationError');

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

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

    return generateAudioReceiveOnlyOffer(pc)
    .then(offer1 =>
      pc.setLocalDescription(offer1)
      .then(() =>
        generateVideoReceiveOnlyOffer(pc)
        .then(offer2 =>
          pc.setLocalDescription(offer2)
          .then(() => {
            assert_session_desc_not_similar(offer1, offer2);
            assert_equals(pc.signalingState, 'have-local-offer');
            assert_session_desc_similar(pc.localDescription, offer2);
            assert_session_desc_similar(pc.pendingLocalDescription, offer2);
            assert_equals(pc.currentLocalDescription, null);

            assert_array_equals(states, ['have-local-offer']);
          }))));
  }, 'Creating and setting offer multiple times should succeed');

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());

    pc1.addTransceiver('audio', { direction: 'recvonly' });
    const offer = await pc1.createOffer(); // [[LastOffer]] set
    pc2.addTransceiver('video', { direction: 'recvonly' });
    const offer2 = await pc2.createOffer();
    await pc1.setRemoteDescription(offer2);
    await pc1.createAnswer(); // [[LastAnswer]] set
    await pc1.setRemoteDescription({type: "rollback"});
    await pc1.setLocalDescription(offer);
  }, "Setting previously generated offer after a call to createAnswer should work");

  promise_test(async t => {
    const pc1 = new RTCPeerConnection();
    t.add_cleanup(() => pc1.close());
    const pc2 = new RTCPeerConnection();
    t.add_cleanup(() => pc2.close());

    pc1.addTransceiver('audio', { direction: 'recvonly' });
    await pc1.setLocalDescription(await pc1.createOffer());

    const offer = await pc1.createOffer();
    await pc1.setLocalDescription(offer);
    await pc2.setRemoteDescription(offer);
    const answer = await pc2.createAnswer();
    await pc2.setLocalDescription(answer);
    await pc1.setRemoteDescription(answer);

    assert_equals(pc1.getTransceivers().length, 1);
    assert_equals(pc1.getTransceivers()[0].receiver.track.kind, "audio");
    assert_equals(pc2.getTransceivers().length, 1);
    assert_equals(pc2.getTransceivers()[0].receiver.track.kind, "audio");
  }, "Negotiation works when there has been a repeated setLocalDescription(offer)");

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

    pc.addTransceiver('audio', { direction: 'recvonly' });
    const sldPromise = pc.setLocalDescription(await pc.createOffer());

    assert_equals(pc.signalingState, "stable", "signalingState should not be set synchronously after a call to sLD");

    assert_equals(pc.pendingLocalDescription, null, "pendingRemoteDescription should never be set due to sLD");
    assert_equals(pc.pendingRemoteDescription, null, "pendingLocalDescription should not be set synchronously after a call to sLD");
    assert_equals(pc.currentLocalDescription, null, "currentLocalDescription should not be set synchronously after a call to sLD");
    assert_equals(pc.currentRemoteDescription, null, "currentRemoteDescription should not be set synchronously after a call to sLD");

    const statePromise = new Promise(resolve => {
      pc.onsignalingstatechange = () => {
        resolve(pc.signalingState);
      }
    });
    const raceValue = await Promise.race([statePromise, sldPromise]);
    assert_equals(raceValue, "have-local-offer", "signalingstatechange event should fire before sLD resolves");
    assert_equals(pc.pendingRemoteDescription, null, "pendingRemoteDescription should never be set due to sLD");
    assert_not_equals(pc.pendingLocalDescription, null, "pendingLocalDescription should be updated before the signalingstatechange event");
    assert_equals(pc.pendingLocalDescription.type, "offer");
    assert_equals(pc.pendingLocalDescription, pc.localDescription);
    assert_equals(pc.currentLocalDescription, null, "currentLocalDescription should never be updated due to sLD(offer)");
    assert_equals(pc.currentRemoteDescription, null, "currentRemoteDescription should never be updated due to sLD(offer)");

    await sldPromise;
  }, "setLocalDescription(offer) should update internal state with a queued task, in the right order");
} // rest

</script>