Huh?<p>Preemptively testing a subset of my code doesn&#x27;t prevent me from fixing other bugs, or from writing regression tests.<p>From the tone of your question, you&#x27;d think that 100% test coverage would fix the remaining 20%, when it clearly doesn&#x27;t.  I mean no disrespect, but this is what I meant when I said that unit-test coverage is a pedantic subject (which, I must again insist, is <i>not</i> meant to imply that you are a pedant).<p>The bugs get fixed, they just don&#x27;t get discovered&#x2F;resolved with up-front unit tests alone.  It ends up being more effective and more efficient to hunt them down by other means.