Tweet by fat
July 16, 2026
For the new editable diffs[dot]com functionality, we pointed agents at existing MIT-licensed editor test suites (Codemirror, Monaco, Atom, etc.) and had them analyze the nearly ~6k tests for missing behavioral coverage. After about 14 hours, we added 195 net new test cases, 30 of which exposed real oversights across selection management, whitespace collapsing, search, history, and more (we now total ~1,281 tests).
- Author
- fat
- Date
- July 16, 2026
- Canonical URL
- /tweets/fat-2077817971511308449-50eeac