This is a testharness.js-based test.
[FAIL] RTCSessionDescription.type is read-only
  assert_throws_js: function "() => {\n    desc.type = 'answer';\n  }" did not throw
[FAIL] RTCSessionDescription.sdp is read-only
  assert_throws_js: function "() => {\n    desc.sdp += 'a=dont-modify-me\\r\\n';\n  }" did not throw
[FAIL] Rejects SDP munging between createOffer and setLocalDescription
  assert_unreached: Should have rejected: undefined Reached unreachable code
[FAIL] Rejects SDP munging between createAnswer and setLocalDescription
  assert_unreached: Should have rejected: undefined Reached unreachable code
Harness: the test ran to completion.