https://zhanwei.wang/en/tags/engineering-practice/Recent content in Engineering Practice on Zhanwei WangHugoen-USMon, 27 Apr 2026 00:00:00 +0800https://zhanwei.wang/en/posts/green-but-wrong/Mon, 27 Apr 2026 00:00:00 +0800https://zhanwei.wang/en/posts/green-but-wrong/<p>Many teams that delegate long-running tasks to AI collaborators keep running into the same uncanny ending:</p> <ul> <li>The task wraps up. CI is fully green.</li> <li>The test report shows hundreds of new specs, beautiful coverage, smooth flow.</li> <li>A few days later, the product ships, and the first real user walks through a core flow — only to trigger a bug that should have been covered but wasn&rsquo;t.</li> </ul> <p>You go back to the code and find: that &ldquo;covered&rdquo; test was actually just a status-code probe; that &ldquo;edge case handler&rdquo; was a <code>console.warn</code> followed by <code>return</code>; that &ldquo;complete feature&rdquo; is missing a database table, a cookie, a middleware — but none of those gaps make any test fail.</p>