title: Disabling *No visible @interface* error for unit test target
body: <p>I have a category (on <code>NSDate</code>) that contains a method that is only called from another method within the category, so there is no need to expose the method in the category's header file.</p>
  
  <p>However, as expected, if I call the method from a unit test, the compiler shouts that</p>
  
  <blockquote>
    <p>No visible @interface for 'NSDate' declares the selector 'myMethod:'</p>
  </blockquote>
  
  <p>I'd like to be able to turn off these particular errors (for the unit test target only, of course).</p>
  
  <p>Can someone point me in the direction of the correct compiler flag?</p>