Basic testing for OfflineAudioContext.length On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS context = new OfflineAudioContext({ length: 100, sampleRate: 44100 }) did not throw exception. PASS context.length is 100 PASS context = new OfflineAudioContext({ length: 1000, sampleRate: 44100 }) did not throw exception. PASS context.length is 1000 PASS successfullyParsed is true TEST COMPLETE