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<title>RTCPeerConnection Set Session Description - Transceiver Tests</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:
// generateAnswer
/*
4.3.2. Interface Definition
[Constructor(optional RTCConfiguration configuration)]
interface RTCPeerConnection : EventTarget {
Promise<void> setLocalDescription(
RTCSessionDescriptionInit description);
Promise<void> setRemoteDescription(
RTCSessionDescriptionInit description);
...
};
4.6.2. RTCSessionDescription Class
dictionary RTCSessionDescriptionInit {
required RTCSdpType type;
DOMString sdp = "";
};
4.6.1. RTCSdpType
enum RTCSdpType {
"offer",
"pranswer",
"answer",
"rollback"
};
5.4. RTCRtpTransceiver Interface
interface RTCRtpTransceiver {
readonly attribute DOMString? mid;
[SameObject]
readonly attribute RTCRtpSender sender;
[SameObject]
readonly attribute RTCRtpReceiver receiver;
readonly attribute RTCRtpTransceiverDirection direction;
readonly attribute RTCRtpTransceiverDirection? currentDirection;
...
};
*/
/*
4.3.1.6. Set the RTCSessionSessionDescription
7. If description is set as a local description, then run the following steps for
each media description in description that is not yet associated with an
RTCRtpTransceiver object:
1. Let transceiver be the RTCRtpTransceiver used to create the media
description.
2. Set transceiver's mid value to the mid of the corresponding media
description.
*/
promise_test(() => {
const pc = new RTCPeerConnection();
const transceiver = pc.addTransceiver('audio');
assert_equals(transceiver.mid, null);
return pc.createOffer()
.then(offer => {
assert_equals(transceiver.mid, null,
'Expect transceiver.mid to still be null after createOffer');
return pc.setLocalDescription(offer)
.then(() => {
assert_equals(typeof transceiver.mid, 'string',
'Expect transceiver.mid to set to valid string value');
assert_equals(offer.sdp.includes(`\r\na=mid:${transceiver.mid}`), true,
'Expect transceiver mid to be found in offer SDP');
});
});
}, 'setLocalDescription(offer) with m= section should assign mid to corresponding transceiver');
/*
4.3.1.6. Set the RTCSessionSessionDescription
8. If description is set as a remote description, then run the following steps
for each media description in description:
2. If no suitable transceiver is found (transceiver is unset), run the following
steps:
1. Create an RTCRtpSender, sender, from the media description.
2. Create an RTCRtpReceiver, receiver, from the media description.
3. Create an RTCRtpTransceiver with sender, receiver and direction, and let
transceiver be the result.
3. Set transceiver's mid value to the mid of the corresponding media description.
*/
promise_test(() => {
const pc1 = new RTCPeerConnection();
const pc2 = new RTCPeerConnection();
const transceiver1 = pc1.addTransceiver('audio');
assert_array_equals(pc1.getTransceivers(), [transceiver1]);
assert_array_equals(pc2.getTransceivers(), []);
return pc1.createOffer()
.then(offer => {
return Promise.all([
pc1.setLocalDescription(offer),
pc2.setRemoteDescrption(offer)
])
.then(() => {
const transceivers = pc2.getTransceivers();
assert_equals(transceivers.length, 1,
'Expect new transceiver added to pc2 after setRemoteDescription');
const [ transceiver2 ] = transceivers;
assert_equals(typeof transceiver2.mid, 'string',
'Expect transceiver2.mid to be set');
assert_equals(transceiver1.mid, transceiver2.mid,
'Expect transceivers of both side to have the same mid');
assert_equals(offer.sdp.includes(`\r\na=mid:${transceiver2.mid}`), true,
'Expect transceiver mid to be found in offer SDP');
});
});
}, 'setRemoteDescription(offer) with m= section and no existing transceiver should create corresponding transceiver');
/*
4.3.1.6. Set the RTCSessionSessionDescription
9. If description is of type "rollback", then run the following steps:
1. If the mid value of an RTCRtpTransceiver was set to a non-null value by
the RTCSessionDescription that is being rolled back, set the mid value
of that transceiver to null, as described by [JSEP] (section 4.1.8.2.).
*/
promise_test(() => {
const pc = new RTCPeerConnection();
const transceiver = pc.addTransceiver('audio');
assert_equals(transceiver.mid, null);
return pc.createOffer()
.then(offer => {
assert_equals(transceiver.mid, null);
return pc.setLocalDescription(offer);
})
.then(() => {
assert_not_equals(transceiver.mid, null);
return pc.setLocalDescription({ type: 'rollback' });
})
.then(() => {
assert_equals(transceiver.mid, null,
'Expect transceiver.mid to become null again after rollback');
});
}, 'setLocalDescription(rollback) should unset transceiver.mid');
promise_test(() => {
const pc = new RTCPeerConnection();
const transceiver1 = pc.addTransceiver('audio');
assert_equals(transceiver1.mid, null);
return pc.createOffer()
.then(offer =>
pc.setLocalDescription(offer)
.then(() => generateAnswer(offer)))
.then(answer => pc.setRemoteDescription(answer))
.then(() => {
// pc is back to stable state
// create another transceiver
const transceiver2 = pc.addTransceiver('video');
assert_not_equals(transceiver1.mid, null);
assert_equals(transceiver2.mid, null);
return pc.createOffer()
.then(offer => pc.setLocalDescription(offer))
.then(() => {
assert_not_equals(transceiver1.mid, null);
assert_not_equals(transceiver2.mid, null,
'Expect transceiver2.mid to become set');
return pc.setLocalDescription({ type: 'rollback' });
})
.then(() => {
assert_not_equals(transceiver1.mid, null,
'Expect transceiver1.mid to stay set');
assert_equals(transceiver2.mid, null,
'Expect transceiver2.mid to be rolled back to null');
});
})
}, 'setLocalDescription(rollback) should only unset transceiver mids associated with current round');
/*
4.3.1.6. Set the RTCSessionSessionDescription
9. If description is of type "rollback", then run the following steps:
2. If an RTCRtpTransceiver was created by applying the RTCSessionDescription
that is being rolled back, and a track has not been attached to it via
addTrack, remove that transceiver from connection's set of transceivers,
as described by [JSEP] (section 4.1.8.2.).
*/
promise_test(() => {
const pc1 = new RTCPeerConnection();
const pc2 = new RTCPeerConnection();
pc1.addTransceiver('audio');
return pc1.createOffer()
.then(offer => pc2.setRemoteDescription(offer))
.then(() => {
const transceivers = pc2.getTransceivers();
assert_equals(transceivers.length, 1);
const [ transceiver ] = transceivers;
assert_equals(typeof transceiver.mid, 'string',
'Expect transceiver.mid to be set');
return pc2.setRemoteDescription({ type: 'rollback' })
.then(() => {
assert_equals(transceiver.mid, null,
'Expect transceiver.mid to be unset');
assert_array_equals(pc2.getTransceivers(), [],
`Expect transceiver to be removed from pc2's transceiver list`);
});
});
}, 'setRemoteDescription(rollback) should remove newly created transceiver from transceiver list');
/*
TODO
- Steps for transceiver direction is added to tip of tree draft, but not yet
published as editor's draft
4.3.1.6. Set the RTCSessionSessionDescription
8. If description is set as a remote description, then run the following steps
for each media description in description:
1. As described by [JSEP] (section 5.9.), attempt to find an existing
RTCRtpTransceiver object, transceiver, to represent the media description.
3. If the media description has no MID, and transceiver's mid is unset, generate
a random value as described in [JSEP] (section 5.9.).
4. If the direction of the media description is sendrecv or sendonly, and
transceiver.receiver.track has not yet been fired in a track event, process
the remote track for the media description, given transceiver.
5. If the media description is rejected, and transceiver is not already stopped,
stop the RTCRtpTransceiver transceiver.
[JSEP]
5.9. Applying a Remote Description
- If the m= section is not associated with any RtpTransceiver
(possibly because it was dissociated in the previous step),
either find an RtpTransceiver or create one according to the
following steps:
- If the m= section is sendrecv or recvonly, and there are
RtpTransceivers of the same type that were added to the
PeerConnection by addTrack and are not associated with any
m= section and are not stopped, find the first (according to
the canonical order described in Section 5.2.1) such
RtpTransceiver.
- If no RtpTransceiver was found in the previous step, create
one with a recvonly direction.
*/
</script>