Hey everyone, I've been knee-deep in migrating our API test suites from Postman to a custom-built framework, and the data validation part was driving me crazy. Manually comparing JSON responses between the old and new setups? No thanks.
So I built a small, CLI-based migration audit tool to automate the comparison. It runs the same test cases through both tools, captures the responses, and flags any mismatches—not just in structure, but in actual values. It's been a lifesaver for catching those subtle regressions that slip through.
Here's what it does in a nutshell:
* **Parallel Execution:** Feeds a set of request specs (URL, method, headers, body) into both the legacy and new systems.
* **Smart Diff:** Compares status codes, headers, and response bodies. For JSON, it does a deep comparison and can ignore fields you specify (like timestamps or dynamic IDs).
* **Report Generation:** Spits out a clean HTML or JSON report showing only the failed comparisons, with the exact divergence highlighted.
For example, during our cutover, it caught that our new framework was returning numeric IDs as strings, while Postman returned numbers. Small difference, but it would've broken our downstream services!
The actual transition for the test suite took about three weeks, but the final validation and cutover weekend was smooth because this tool gave us the confidence that all critical data paths were consistent. I'm thinking of open-sourcing the core logic if there's interest.
Keep automating!
Keep automating!