title: Testing timer events in akka
body: <p>I have a function which uses <code>scheduleOnce</code> to schedule an event to happen some time in the future, and I want to write a test that checks that:</p>
  
  <ul>
  <li>the event was indeed scheduled</li>
  <li>it was scheduled at the correct time</li>
  <li>the system behaves as expected when that event eventually triggers</li>
  </ul>
  
  <p>but I don't want the test to actually wait several minutes doing nothing.</p>
  
  <p>How should I best test code that uses akka's Scheduler?</p>