title: Why is this test not tautological?
body: <p>This is not about explicit code, so apologies if it should have been posted elsewhere. It is, however, solidly within the domain of testing, which I assume you guys to be right at home in.</p>
  
  <p>I'm reading the provocatively titled paper <a href="http://rbcs-us.com/documents/Why-Most-Unit-Testing-is-Waste.pdf" rel="nofollow">"Why Most Unit Testing is Waste"</a> (21 pages) and came across this passage:</p>
  
  <blockquote>
    <p>The third tests to throw away the tautological ones. [...] Testing for  <code>this</code> being non-null on entry to a method is, by the way, not a tautological test — and can be very informative [...]</p>
  </blockquote>
  
  <p>This really piqued my curiosity -- why would <code>this</code> <em>ever</em> be null <em>on purpose</em>? <em>How</em> would you even write such code?</p>
  
  <p><em>Edit:</em> Thank you Daniel! I don't know much C(/++/#) but my initial (Java-centric) thought was that <strong>no, it's not possible</strong>, and I seem to be right, with reference to your 2nd comment that <em>"If you're using this, then you're in the instance so this [can't be] null."</em></p>