### Question:
TextUI { public void update() { while (!demuxer.isSuiteFinished()) { Event<SuiteListener> message = eventStream.poll(); if (message == null) { break; } updateWithMessage(message); } } TextUI(MessageReceiver<Event<SuiteListener>> eventStream, Printer printer); void setPassingTestsVisible(boolean passingTestsVisible); void setProgressBarVisible(boolean progressBarVisible); boolean hasFailures(); void update(); void updateUntilFinished();  }### Answer:
@Test public void can_update_non_blockingly() { ui.update(); assertNotInOutput(SUMMARY_LINE); }