Vendor-published Test migration
Asana finishes a five-year Enzyme → React Testing Library migration in two weeks with Codex
From a five-sentence prompt, up to four Codex agents worked in parallel, each on a separate copy of the codebase. An engineer checked progress twice a day and reviewed every change. Enzyme was fully removed after 1.5 weeks of engineering effort spread over two calendar weeks.
The numbers (as reported)
| Calendar time | ~2 weeks |
|---|---|
| Engineering effort | ~1.5 weeks |
| Parallel agents | Up to 4 |
| Model + infrastructure cost | ~$12K (model ~$11K, infra ~$1K) |
| Projected time at prior pace | ~5 more years |
| Estimated manual cost | ~$6M fully loaded (Asana estimate) |
Facts
- Company / subject
- Asana
- Tools
- OpenAI Codex
- Codebase
- brownfield
- Work type
- Test migration
- Stack
- React, Enzyme, React Testing Library
- Published
- 2026-08-19
- Last checked
- 2026-10-17
Caveats
Published by OpenAI; Asana's own post notes it is part of a partnership with OpenAI. The $6M figure is Asana's back-of-the-napkin estimate.
Source
OpenAI customer story (Asana also published its own account, in partnership with OpenAI)
Also: https://asana.com/inside-asana/migrating-off-enzyme-2-weeks