[RTCPeerConnection-setLocalDescription-offer.html]
  [setLocalDescription with type offer and null sdp should use lastOffer generated from createOffer]
    expected: FAIL

  [setLocalDescription() with offer not created by own createOffer() should reject with InvalidModificationError]
    expected: FAIL

  [Set created offer other than last offer should reject with InvalidModificationError]
    expected: FAIL

  [Creating and setting offer multiple times should succeed]
    expected: FAIL