https://blog.abhipraya.dev/tags/property-based-testing/Recent content in Property-Based-Testing on Daffa AbhiprayaHugoen-us© Daffa AbhiprayaThu, 09 Apr 2026 00:00:00 +0700https://blog.abhipraya.dev/ppl/part-a/tdd/Thu, 09 Apr 2026 00:00:00 +0700https://blog.abhipraya.dev/ppl/part-a/tdd/<p>We had 91% line coverage and felt good about it. Then we ran mutation testing and scored 0%. Every line of our service layer was executed by tests, but almost nothing was actually verified. This is the story of how we discovered the gap between &ldquo;code was run&rdquo; and &ldquo;code was checked,&rdquo; and what we changed to close it.</p> <blockquote> <p><strong>Note:</strong> Our project is hosted on an internal GitLab instance, so we use the term <strong>MR (Merge Request)</strong> throughout this blog. If you&rsquo;re coming from GitHub, MRs are the equivalent of <strong>Pull Requests (PRs)</strong>.</p>