https://rjrowland.com/tags/testing/Recent content in Testing on rjrowlandHugoen-usFri, 24 Jul 2026 09:00:00 -0500https://rjrowland.com/posts/engineering-practices-code-quality/Fri, 24 Jul 2026 09:00:00 -0500https://rjrowland.com/posts/engineering-practices-code-quality/<h2 id="characterization-tests-one-dimension-at-a-time">Characterization tests, one dimension at a time</h2> <p><em>The term &ldquo;characterization tests&rdquo; comes from Michael Feathers&rsquo; <a href="https://www.oreilly.com/library/view/working-effectively-with/0131177052/" target="_blank">Working Effectively with Legacy Code</a>.</em></p> <p>Refactoring without tests isn&rsquo;t refactoring. It&rsquo;s rewriting with optimism. &ldquo;Looks equivalent&rdquo; is not &ldquo;is equivalent.&rdquo; The subtle behavioral change hiding in an untested path finds its way to production six months later, <code>git blame</code> points at a commit that moved some files around, and nobody can tell what the intended behavior even was.</p>