webrtc/RTCPeerConnection-description-candidate-replaced.https.html

<!doctype html>
<meta charset=utf-8>
<title>RTCPeerConnection description attributes are replaced, not mutated, by candidates</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
'use strict';

const remoteCandidate = 'candidate:1 1 udp 2113929471 192.0.2.1 50000 typ host';

function assertReplaced(before, sdpBefore, after, {candidate}) {
  assert_not_equals(after, before, 'attribute is a new object');
  assert_equals(before.sdp, sdpBefore, 'old object sdp is unchanged');
  assert_equals(after.type, before.type, 'type is preserved');
  // Browsers may reorder or drop extension attributes (e.g. ufrag) in SDP.
  candidate = candidate.split(' ').slice(0, 8).join(' ');
  assert_false(before.sdp.includes(candidate), 'old object still lacks candidate');
  assert_true(after.sdp.includes(candidate), 'new object has candidate');
}

promise_test(async t => {
  const pc = new RTCPeerConnection();
  t.add_cleanup(() => pc.close());
  pc.addTransceiver('audio');
  await pc.setLocalDescription();
  const before = pc.pendingLocalDescription;
  const sdpBefore = before.sdp;
  assert_equals(pc.pendingLocalDescription, before, 'same object across gets');
  const {candidate} = await new Promise(r => pc.onicecandidate = r);
  assert_equals(pc.localDescription, pc.pendingLocalDescription);
  assertReplaced(before, sdpBefore, pc.pendingLocalDescription, candidate);
}, 'pendingLocalDescription is replaced, not mutated, by a gathered candidate');

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');
  await pc2.setRemoteDescription(await pc1.createOffer());
  await pc2.setLocalDescription();
  const before = pc2.currentLocalDescription;
  const sdpBefore = before.sdp;
  assert_equals(pc2.currentLocalDescription, before, 'same object across gets');
  const {candidate} = await new Promise(r => pc2.onicecandidate = r);
  assert_equals(pc2.localDescription, pc2.currentLocalDescription);
  assertReplaced(before, sdpBefore, pc2.currentLocalDescription, candidate);
}, 'currentLocalDescription is replaced, not mutated, by a gathered candidate');

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');
  await pc2.setRemoteDescription(await pc1.createOffer());
  const before = pc2.pendingRemoteDescription;
  const sdpBefore = before.sdp;
  assert_equals(pc2.pendingRemoteDescription, before, 'same object across gets');
  const candidate = {candidate: remoteCandidate, sdpMid: pc2.getTransceivers()[0].mid};
  await pc2.addIceCandidate(candidate);
  assert_equals(pc2.remoteDescription, pc2.pendingRemoteDescription);
  assertReplaced(before, sdpBefore, pc2.pendingRemoteDescription, candidate);
}, 'pendingRemoteDescription is replaced, not mutated, by addIceCandidate');

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');
  await pc1.setLocalDescription();
  await pc2.setRemoteDescription(pc1.localDescription);
  await pc2.setLocalDescription();
  await pc1.setRemoteDescription(pc2.localDescription);
  const before = pc1.currentRemoteDescription;
  const sdpBefore = before.sdp;
  assert_equals(pc1.currentRemoteDescription, before, 'same object across gets');
  const candidate = {candidate: remoteCandidate, sdpMid: pc1.getTransceivers()[0].mid};
  await pc1.addIceCandidate(candidate);
  assert_equals(pc1.remoteDescription, pc1.currentRemoteDescription);
  assertReplaced(before, sdpBefore, pc1.currentRemoteDescription, candidate);
}, 'currentRemoteDescription is replaced, not mutated, by addIceCandidate');
</script>