Unit tests do not correlate to quality, and even at 100% coverage only guarantee that you&#x27;ve looked at every line of code twice (usually).  Not only that, a lot of projects skip adding testing until well after a proof of concept is working... why?  because we don&#x27;t want to not ship features for two weeks while we backport in tests... Now you have less than optimal code <i>and</i> less than optimal tests.<p>This persists, every suggestion to refactor structure rebuffed, and this persists until the code debt is so high, it takes 4-5x as long to add a feature as it should.  Where, if you&#x27;re lucky, you can make a new version using only 3-5 year old technology, instead of the decade old stuff you&#x27;ve been supporting for half a decade.  Even then the 2-5yo stuff isn&#x27;t as nice as it was sold, but it&#x27;s &quot;enforced&quot; by the company powers that be (god I hate angular sometimes).