I'm all about testing.  I do my best to adhere to test-driven development (though, admittedly, sometimes that's hard when you're doing some experimental work just to see if something's possible).  I even go as far as mocking full page request lifecycles to test controls and page behavior.

But say you have a little code block like this:

if(!initialized)
{
  lock(syncroot)
  {
    if(!initialized)
    {
      Initialize();
    }
  }
}

Standard lock/double-check stuff to ensure things only get initialized once.  Does anyone have a good way to test that?  A quick search of the net turns up... well, pretty much nothing.