title: Test cases for a program using System Clock
body: <p>I recently had an inteview and inteviewer asked me this.
  Suppose We have a program that depends on system Clock. How will you test this program or write test cases.</p>
  
  <p>I answered following</p>
  
  <ol>
  <li>Have program provide an API to set the time an when set program needs to take this time instead of Sytem time</li>
  </ol>
  
  <p>He then asked me how will you test the production Issue?</p>
  
  <p>Can someone put some highlights on this question?</p>
  
  <p>Thanks.Rick</p>